I think I bought mine for $150 including the battery and charger. Money well spent, if you ask me (certainly cheaper than hiring a plumber). Before that I had a manual version similar to the one you linked to, but it just didn't cut it in my last case of a clogged kitchen drain.

The nice thing about the automatic version is that you can go in/out and clockwise/counterclockwise independently and with a simple switch, which makes it easy to route through complicated pipe geometries without getting stuck, and you don't even have to apply much force because the machine does that for you.