I has a belly button
Seriously though... that's the way it is. You can't buy from the states, because the border police will find, seize, and in all likelyhood blow up your new toy in a puff of magic smoke and underware gnomes. So buying cheap guns from the States is out.
Because quality airsoft is hard to get in country the prices are near sky high, that's just a part of the sport, if you're not willing to pay the prices shown, you won't get a gun. Get age verified and look on the classifieds here on ASC (more on AV later)
007 is concidering getting guns with clear bodies in to sell in Canada, there are debates as to the quality of these, but they should be pretty good, in a few months that could be a source for you as the prices should be around what you'll see on american sites. $300~ if I'm not mistaken.
Age verifying... it will only happen in person. Don't like it, don't bother going on. Anyone can fake a drivers license to show via the "scanned and emailed" path. The only way to combat kids faking their way in, is to meet people in person and show ID there.
Your best bet is to go to a game and ask questions there to people who've been around for a while. You'll learn more there than you will here.
And read the FAQ
