How do I make a 1981 mustang look beautiful for cheap?
That's a trick question... Right?
Ya see, here's the immediate problem. "Beautiful" is a very subjective word open to a lot of interpretation. Some people think the crap they do on Pimp My Ride makes a car beautiful. Some people think being stock and fully restored makes it beautiful. My idea of beautiful is probably different from yours.
Now let's explore the word "cheap". Pretty much everything I've already said also applies. Besides, if you have to pay to have the work done, cheap is not going to be cheap.
Don't let any small minded meatheads take away your enthusiasm. An '81 'Stang can be turned into a REALLY nice car, but you need to put some time into defining the two key words above.