$450 should be your target (includes battery). 400 at the bare minimum.
It's good to have all your gear sorted out.
I'm going to assume you live in the sticks here so airgun discharge is OK. If you live in the city (or outside the city but are administered by a city) you should note any bylaws or you could face fines (sometimes a warning but can range from $50-500+ depending on bylaw officer and what the local bylaw statutes are). ALSO you should be VERY VERY safe, and make sure no member of the public can see you or in any way possibly pass by. Worst case scenario could be that the ERT is called on you guys and you get arrested or w/e (and charged with bylaw violations if they deem necessary).
Whatever you choose IMO 450 is about the right price point (for gun) for getting into the sport. I'd say 650-750 total (includes gear, charger, other accessories, etc.)
May I ask how old you are though? If 16+ maybe you could ask your local club/field if you can observe or join in. It's a different culture there as opposed to Ontario, as opposed to the Prairies, as opposed to the Pacific coast, and even then there are sometimes small local groups that will let you play. Case in point, "EASY group" (Edmonton AirSoft Youth), is a club of youth who play and AFAIK are somewhat supported by EAR (the local 18+ group) since they run a good club, have a good system, are safe and all that.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE