Here's a small sampling form one retailer, most are $20. There's dozens of retailers. http://www.shortyusa.com/cart/index.html?UID=1133105053-69.169.173.79&RID=1&NL=&kiosk=
You want to look at spring pistols, not gas or electric, because springers will be cheap. Sizes are pretty damned close, if not exact. I can't tell the difference between my airsoft Glock 17 and a real Glock 17.
On the other hand, Botach has blue guns for $36 each, that doesn't seem like a terrible price for a pattern: http://www.botachtactical.com/blueguns.html