First, never get a wireless one. They're usually a pain with needing to be charged and they almost always have more input lag than wired mice. And the ones that don't have a slower response rate are always a lot more expensive. They're not really worth it.What kind of gaming mouse are you thinking of? Something simple and classic, something with a few more buttons and settings, or something with like 20 buttons and macros on there for MMO's and whatnot? And what do you consider "somewhat affordable"? You'll find gaming mice for anywhere between 30$ to into the 100's. Gotta be a bit more specific than that.
Use your laptop trackpad, obviously.
My Razer Deathadder has served me quite well.