I love my stool. It does raise and lower, and it's on wheels so I can move easily. It's very comfortable, although I think I need to raise my torch because I seem to be slouching. There is also a version with a small backrest. It came from Wal-Mart, the link is here:
http://www.walmart.com/ip/Ergonomic-...hrome/10778744
Available in multiple colors, too!