Scratch-X comes in a tube, and there isn't much of it. You would use up alot to do a whole truck. I use their Body Scrub product, which is a more concentrated version of Scratch-X. It comes in a bottle, so you get more. Using an orbital buffer, there are few scratches that Body Scrub can't remove.
Body Scrub used to be available at Discount Auto Parts, but now I have to mail order it from Meguiars. Discount AP now just carries crap, but maybe PepBoys will have it. Seems like all the Auto parts places now carry the same products.