It purely depends on what you want to go with in terms of your load out.
Going with SOF or western world's soldier is almost guaranteed money pit.
LE loadout are generally poor choice because they tend to use black (atleast the commonly associated ones) black stands out.
PMC loadout are pretty much whatever you like.
If you are into representing a particular conflict nothing beats being bad guys
A 7.62mm AKM will fit in almost every scenario outside of WWII and earlier.
Gears are cheap;
Load bearing device: A chicom chest rig or Russian Lifchik
Clothing: Civilian work fantastically (T shirt plus jeans) with either 3/6 coloured desert or M81 woodland jacket works extremely well
Headgear: balaclava or Shemagh depending on which area of baddie you're representing
If AK isn't your thing, go with a M16A2 and use LBV-88 chest rig instead and keep the rest as is.
One thing is for sure, make sure you get good hiking boots and military rated eye protection