You pretty much got what you paid for. im assuming you got a single stage paint job that had clear mixed in it. most body shops color sand and buff the car after it has been painted and majority of the time its a 2 stage paint job or 3 stage depending on what color it is. yes prep work has a lot to do with it. also a good paint job will range anywhere from 3-10k depending on color, the shop, and how detailed you want the work.

just fyi dont try to buff your own car if A. YOU HAVE NEVER DONE IT BEFORE AND B. IF ITS A SINGLE STAGE. IT CAN BE DONE BUT PAY SOMEONE TO DO IT.