I wrote a tutorial at Spray-painting your uni
I agree that a clear coat finish is highly recommended… your spray job will last much longer with the clear coat than without.
I don’t agree that you’ll be spending near $50. Three cans of paint plus sandpaper will set you back $15 at most hardware stores. What you will be spending is time. But as an added bonus, you get the pride that comes from being a do-it-yourself’er!
Good luck.