I did it my self using a product called Raptor Liner, 2-3 coats on the sides and 3-4 coats on the floor. I removed all rubber gaskets and mounting screws, scuffed with 150-200 grit and scotch brite pad (it was a little odd sanding on a 2 week old truck
), mineral spirit cleaned, and threw down etch primer first. Then sprayed it with the included gun. I have $160 invested. I have hauled lumber, metal, multch, and random stuff. No issues but some minor scratches that your would get with any heavy use. No chips what so ever and it looks awesome.
All back together: