A number of good well-known US-based retailers include:
www.airsoftarms.com
www.airsoftatlanta.com
www.airsplat.com
www.poweredgeusa.com
www.airsoftgi.com
If you're looking for a starter gun, well, there are lots. You get what you pay for.
-Spring Pistols: The lowest of the Airsoft color spectrum. These work by racking the slide for each shot fired.
Good: Any Tokyo Marui High Grade Hop Up models. >40 bucks.
Bad: Any thing less than $35.
Range: At the most, 90ft, Least, 20.
Verdict: For starting at the pure base of airsofting.
-Mini Electrics. These work by using cheap commonly avalible batteries with a motor to cycle a piston and a cylinder to compress air to power the BB.
Good: Most of them are ok. They won't last very long though.
Bad: Nearly all of them.
Range: Won't reach across your living room.
Verdict: If you can upgrade them to 400fps and last a decade, you're a genius. Fun for close plinking and very close CQB. Otherwise, avoid.
-Spring Rifles: Same thing as spring pistols, but you cock a handle instead.
Good: MP5SD3 by forgotwho. Best in the business.
Bad: Dunno. A lot of them are fair, however.
Range: Since most average about 230fps, these might reach across to your living room.
Verdict: If you like it and want it, get it. But there are better ones...see below.
-Gas Rifles/Gas Pistols: Now you've reached into the upper spectrum of the Airsoft world. Gas pistols work by gas stored in the magazine. Rack the slide (for Gas Blowbacks, like real ones), which charges a bb, and when you fire, unleashes a gush of gas which propels the bb. Non-blowbacks (NBB) are excellent on gas consumption and power, as some can tap 400 fps. The gas goes straight to propelling the BB. Rifles work in similar ways, but "Classic" rifles work a little like Paintball guns. Gas rifles tend to be more rare than spring rifles or AEGs.
Good pistol: KJW 1911, (poweredge) KSC/KWA G19, Tokyo Marui M9, KWC "Super" Berreta 92F.
Bad: There are lots, so join a message board (a good one would be
www.airsoftcore.com) and ask around.
Range: Definitely across your living room.
Verdict: If you spend for a better model, you won't regret it.
-AEGs: This is the top-of-the-line for the airsoft market. Basically the best models are the recent Classic Army models, Tokyo Marui, and the new KSC models.
Good: Described above.
Bad: Ask around message boards. There are lots of mixed reviews, however. Most of the recent AEGs born by TM and CA are excellent.
Range: Up to 230ft.
Verdict: Ask around for the best models.
There you go, a rough stamped-out response. You can start by reading the beginner's guide at
www.renegaderecon.com. It's on the middle left directory. Then join
www.airsoftcore.com, read the forums a little, propose a proposal which would propose a proposal to buy X guns......
Ok I'm done.