Sorry to say this but you're going to have to spend at least $600 for a NIB stock M14, and probably around $800 for one that's been upgraded.
Also it has a V7 mechbox, which IIRC is really hard to work on unless you have 4 hands (or lots of manual dexterity). This is just what I've heard though.
Any other gun it's possible to get a decent clone but with the M14 it's probably better to get the TM M14.
If you're on that much of a budget either save up, or buy a pistol and game that at a CQB field. Otherwise sorry but this sport isn't for you. I've personally spent ~$1100 on stuff already (and I'm a student who needs to pay for tuition, books, food, and stuff). I'm not trying to be elitist but that's just the consequences of being in Canada and wanting to play airsoft. You're either going to have to move to the US, Asia, or Europe if you want to play for cheaper.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE