I have a 2009 sliverado 4x4. I'm trying to put a 6 inch suspension lift on it and was what's the best one for the best price?

 

Full throttle suspension makes a good 7" kit, fabtech has a good 6" kit that really gives you 8" of lift, Cognito is another good one, and mcgaughys is another good lift. It's all about how much you want to spend. These lifts all give you flat angles at the height advertised so you can go higher later if you want to. If it were me, I'd be lookin at the mcgaughys kit or the full throttle kit. Both can run the bilstein 7-9" shocks for a really smooth ride set at 7" or you can run em at 9" for a decent ride.