Buy a quality one it's worth it. I have cordless milwaukee 3/8" impact gun that came with a drill, flashlight, 2 batteries and charger I paid $400 for and it works really well. Also have 1/2" snap on cordless impact. One of the best items i purchased. That goes for $500ish for 2 battery, charger and sweet case. I use both of them 5 days a week and they hold up well to shop abuse.
P.S...I'd buy the snap on 3/8" set if I were to do it again.