I have a 2004 Chevy suburban 1500 it has the Bose system OnStar TV in the bag and the controls on the steering wheel I need to know what kind of harness I need for an aftermarket radio and I really don't use the OnStar so is anybody can help me out what I can do or find a cheaper way to go with this

 

Since this is a site devoted to HHR we would have no way of knowing.
Maybe you could try at a forum devoted to Suburbans, or try Crutchfield.com, they offer free advice and good catalog.