Stop in for a cup of coffee
I'm not a body man but I did sell guns to many guys that were. I got to where I wouldn't take one in on trade because they were worn out. Most used guns are well used and aren't good for much more than primer. (depending the air cap and needle size) Depending on how professional you want to get, you would be better off getting a Harbor Freight or Eastwood gun for low buck. All the big brand names are going to be quite spendy.