I have those rubber honeycomb matts. They are pretty nice, especially now that winter is coming. I don't know how much they cost because mine came with the car FREE!!! I also got the Gorilla Gear FREEEE!!! haha, my dealer rocks. Anyway, you could buy some generic rubber matts at your local auto parts store. They wouldn't fit as nicely as the VW matts but I'm sure they would be much cheaper.
I got the rubber "GTI Monster Mats" and Gorilla Gear for free with my '06 as well! Can't say much for keeping the cloth mats clean short of taking off your shoes, but you should be able to just clean them with a hose if you want to wash them or beat them with a stick to get dirt off them. Also, if you want some of the official rubber ones you should be able to get them through your dealer, or you can order them from http://drivergear.vw.com for $76.