Almost any pistol that's decent will hit your for about $400.
The KWA is fine, they build the uber nice KSC stuff for Japan and the no-trades stuff for the rest of us. Some folks find the factory markings a bit ugly but if you're gaming with it then it doesn't matter.
I'd suggest this flavor myself. http://www.kwausa.com/products_kp45_tactical.html
As for the fine details of how and where to find that'll come down once you get yourself age verified on this website, that will let you access a restricted area where that subject is discussed in the open.