Avoid buying from places like GSCI, Alpha Optics, etc. Surprisingly, the best place to get NVGs and related devices in Canada is here through the ASC classifieds, as some users have huge collections of NVGs and related kit, and others buy and sell once in a while.
The current average price of a relatively new, thin film, autogated PVS-14 in Canada is roughly $4000. Used or lower spec ones are typically $3500, some janky ones are around $3000.
Legality
Nightvision is legal to own in Canada, however it is export restricted from the United States without paperwork. Therefore, you should buy from within Canada.
Mounting and Systems
It is generally advisable to use a head mounted system. If you get a scope, are you going to walk around with your gun shouldered?
To put the a NOD in front of your eye, you generally need the following: A helmet, a shroud, a mount, and an arm if you are using a monocular.
Helmets
While you don't necessarily have to use a helmet, you can use a nightcap or skullcrusher as well, the helmet is the most popular. Skullcrushers are uncomfortable. The Crye nightcap is okay and functions like a helmet, it has padding underneath the shroud and has velcro for counterweights.
With helmets, it is generally advisable to use a reputable brand of helmet. Clone helmets work, but would you trust several thousand dollars of your gear hanging off a cheap helmet?
The most popular helmets are the OpsCore bump, and Team Wendy bump. They are both plastic bump helmets with integrated, non removable shrouds. It is also recommended to use a counterweight on the back of your helmet so that the front does not slide down over your eyes when you are trying to use your NOD.
Shrouds
The shroud is the interface on the front of the helmet where the mount secures to your helmet. Most bump helmets have shrouds molded into the front face of the helmet, however ballistic helmets use other methods for attachment. There are old school ratchet attachments and single hole shrouds, however you should stick to the standard triangular 3 hole shroud that has one hole at the top, one hole bottom left and one bottom right. These are screwed into the helmet shell.
The most common shrouds are the OpsCore VAS, OpsCore Skeleton, and Wilcox L4 shroud. They are all pretty much the same thing, I prefer the OpsCore Skeleton shroud since it is made of one piece of metal instead of plastic with a metal insert.
Mounts
Mounts attach your NOD to your shroud and flip your device up and away or down so you can see through them. Mounts are either Force to Overcome (FTO) meaning they use detents and are flipped up and down by force to overcome the detents, or are push button mounts that use a push button to release the swing arm mechanism.
Mounts are generally bayonet, ANVIS, or dovetail. Bayonet is old, shitty, wobbly, but works. ANVIS is for aviation style mounts only, and is proprietary because the power runs from a battery pack, through the mount, and powers the NVG. ANVIS stuff kinda sucks so stick to dovetail. Dovetail is more or less the standard. It uses a dovetail shoe and is generally a stable and secure mounting surface.
Mounts attach either to arms if you have a monocular, and directly to your NVG if you have a binocular setup, or a monocular setup with a built in dovetail such as a PVS-18.
The most common mounts in Canada are the USGI Rhino, Wilcox G24, Norotos AKA2, and Norotos INVG.
The USGI Rhino is a FTO mount and uses a bayonet mount that is meant to interface with a USGI J Arm or a PVS-7. This mount is cheap, it sort of works, wobbles like crazy, and should be avoided. All other mounts mentioned use the dovetail interface.
The Norotos AKA2 is available in FTO or push button. It is an excellent mount. This mount can store the NVG in front of the helmet or above the helmet.
The Norotos INVG is a FTO only mount and is meant for use with monoculars. It allows you to rotate the NOD after it is flipped up so that it is stored closer to the helmet, allowing for a more relaxed balance and lower profile. Basically useless feature if you run binoculars.
The Wilcox G24 is similar to the AKA2 but is only available in push button. it only flips the NOD out in front of the helmet, but does so in a much lower profile manner than the AKA2. Wilcox mounts are notorious for developing wobble over time due to the pin system used to lock the push button. The G24 family of mounts are my personal preference. I run a G66 and G30, basically G24s with a built in shroud and lanyard that is more stable, lower profile, and lighter than a conventional setup but costs $$$$.
Arms
Arms attach your monocular device to your mount, and generally allow you to swap from left handed to right handed use.
USGI J Arm
This thing uses the bayonet adapter and pairs with the USGI Rhino. Wobbles like crazy, generally known to be shit, but works if you're on a low budget.
Norotos DDA
DDA stands for Dual Dovetail Adapter. It is a solid block of plastic with a screw that attaches to your monocular, and has one dovetail on each side so you can use one attachment for right eye, and you simply remove and use the other dovetail shoe for left eye. It is the most stable of the arms, however it lacks any vertical adjustment, and only the newest versions have horizontal adjustment - and only on one side. The other side is non adjustable unless you remove both shoes and switch them around. The older DDA is completely non adjustable. I don't like the DDA because it blocks a lot of the field of view on the non NOD eye, and swapping sides in the dark isn't as easy as the push button on the Wilcox offering.
Wilcox J Arm
The Wilcox J arm is basically a swing arm that screws into the monocular. It is adjustable vertically and horizontally by adjusting the angle of the swing arm. The swing arm is held in place by a push button, that is used to switch from one side to the other, which is convenient for CQB situations.
Optics
To aim your gun, you will need either a NVG compatible optic, or a laser. Most airsoft optics will be too bright on the lowest setting to be usable under NVGs, however some clones will work.
For optics, I would recommend Holosun if you are on a budget, or Aimpoint and EOTech if price is not an issue. While I run both Aimpoint and EOTech, I prefer Aimpoint due to its simplicity. However, one big advantage with EOTech is when you are transitioning from NVG optic to regular optic, it can be done so with the press of a single button, whereas with an Aimpoint you have to find the knob, and adjust it to the desired brightness.
You can look through a NVG compatible optic with your NVG as if it were a normal optic.
Lasers and Illumination
Lasers are not absolutely necessary, but are definitely cool. For airsoft in Canada, game hosts generally require eye safe IR (infrared) lasers. Eye safe IR lasers have a power output of 0.7 mW or less. The power has to be extremely low as the human eye will have no natural blink reflex, since it cannot see the laser. Do not use clone lasers such as the G&P DBAL, they are not eye safe. Some people will say they can modify them to be eye safe, but that is up to your local game host whether or not that will be recognized, as its the same reason you aren't allowed to bring shit like home made pyro.
The quality or "gucciness" of the laser doesn't really matter that much for airsoft, since it would have to be a really, really shitty laser to not work past 100m which is more than any airsoft engagement realistically takes place.
The most common lasers are Lasermax and Crimson Trace lasers for those who just want something cheap. People that want operator points will look at Steiner Optics and L-3. Steiner's CQBL, DBAL I2, and DBAL A3 seem to be the most popular. Some people also like the L-3 ATPIAL-C, which is the civilian eye safe version of the military PEQ-15.
Some laser devices have built in illuminators such as the PEQ-15, and DBAL A3. These are lower power than floodlights, but help with target identification. Do note though that while most full power illuminators are focuseable, many eye safe illuminators are non focuseable to prevent the illuminator from being focused into a non eye safe beam. The ATPIAL-C is an example of this, whereas the full power PEQ-15 has a focuseable illuminator.
Floodlights are basically infrared flashlights. As far as floodlights go, the most common ones are the Surefire Vampire series, and some of the Inforce light offerings. Inforce is cheap and works, but forces you to use the existing switch. Surefire is more expensive, but gives you the freedom to use a remote switch.
Housings
There are tons of different housings on the market and its very confusing, I will touch on the ones I have experience with or know something about. If you have direct experience you'd like to add, please share.
Monoculars:
PVS-14
Standard, most common monocular housing, adjustable gain. Made of injection molded plastic, relatively durable. Has a built in IR illuminator and is a good all 'round housing. Several battery compartments available ranging from 2 AA to single CR123.
AB NVM-2AA and AB Pitbull
Aftermarket monocular housings made by AB Nightvision. NVM-2AA uses 2 AA batteries, Pitbull uses CR123, otherwise they are the same. Made of CNC machined Delrin, fixed gain. Some are made for PVS-14 optics, some are made for ANVIS optics, which are in my opinion superior to the PVS-14.
MUM-14
No experience. Lighter PVS-14 style housing.
Vyper-14
No experience. Reinforced PVS-14 style housing.
PVS-18
No experience. Monocular housing, uses PVS-15 optics which are superior to PVS-14 optics. Has a built in dovetail so does not require an arm adapter.
Binoculars:
AN/AVS-6/9
Aviation housing, fixed gain. Uses a bridge and wormdrive to adjust interpupillary distance. Made of injection moulded plastic, known to be fragile and kind of shitty. Only uses ANVIS mounts and external power sources.
PVS-15
No experience. Made of injection molded plastic, interpupillary distance adjusted via swinging pods. Durable, but heavy.
BNVD
No experience.
AI Sentinel
Adams Industries looked to improve upon the AN/AVS 6/9 devices. They were sought after because the AVS optics gave a clearer image than PVS-14 optics, however AI addressed the shortcomings in durability. The Sentinel is a very durable housing made of CNC machined aluminum and Delrin. It uses a wormdrive with detents to adjust interpupillary distance. They can be made for either PVS-14 or AVS optics. Generally fixed gain, can run off a CR123 or use an ANVIS mount and external battery pack.
AB Mod3
Similar to the Sentinel, except the moncular pods can detatch from the bridge and be inserted into monocular adapters to be used as two separate monoculars for two different people. Made of CNC machined Delrin with an aluminum bridge, uses gold plated contacts from the battery to the pods. Can use one CR123 or an external power supply with an ANVIS mount. Monocular pods can only use CR123. Are made to accept either AVS or PVS-14 optics. A bit more wobble than the Sentinel, and not as durable, but this is my preferred housing.
AB RNVG
No experience. Runs off AA, meant to be more rugged and compete with the Sentinel.
ACT DTNVG
Made in Luxembourg, each pod can flip up individually. Pods turn off when flipped up. Fairly lightweight, can be made for either PVS-14 optics or AVS optics. Fairly expensive, and durability of the pod hinge joints is a concern.
L-3 PVS-31
Non serviceable, made of injection molded plastic. Uses GPNVG optics. Very clear image, but don't count on getting one as these are restricted to military, law enforcement, and cool guys only.