MoreBeer is just selling Mark's Keg Washer. This HBT thread has a few pictures and gives the keg washer a thumbs up.
You can buy the keg washer directly from Mark's if you're so inclined. I really want one but am holding off until the new year or maybe I'll try one of the DIY replicas.
I've blown a lot of money in my rush for instant gratification. One of the things I'm still learning is to shop around before buying, especially when buying from one of the majors like NorthernBrewer or MoreBeer. Look for retailers selling the same product for a lower price and look for lower...
I second GuldTuborg, "Avoid Blue Rhino like the plague." I bought a new, empty tank from Costco and then filled it up at a local gas station for under $20.