Okay, so when I got into airsoft, the first thing i wanted to know was, "where can i get one of these"? then "which one do i want?" Well, this will help you choose.
Step 1: Cheap Vs Expensive & Types of Guns
Well, it all depends on what you will be using your gun for.
LPEG (Low Power Electric Gun)If you want to do backyard skirmishes and never any real battles, when you would be fine with a LPEG
AEG (Automatic Electric Gun)If you want to do battle, then you will want a more expensive AEG. These AEGs range from $80-2000.
Springer: Most people's first gun.Good for backyard skirmishes, but unless you have a high end spring sniper, avoid these on the battlefield.
GBB (Gas Blow Back) a few rare assault weapons are powered by gas Pistols often are.
GNB:Gas Non Blowback. Generally reserved for cheaper pistols, but expensive ones can be this, also.
Full auto is a clear advantage. Also, don't buy cheap guns for a war. Pictured above, Top: good ECHO 1 G36. Below: Crappy Crosman Mosberg Spring gun