actually I don't think you can buy directly anymore, but if you google it you'll find a bunch of online dealers. best to go to a local dealer and look at the swatch book in person, online colors are not accurate.
personally, I think it's best to have a shop install them. I did a katskin set on a pickup truck (that was just 2 seats) and it was not easy. there is an art to making it fit right and I think that the $400-500 labor charge to do the 5 is $ well spent. but if you're on a tight budget and you have some time and patience...(RTM)