I haven't used one, so really can't advise. However, several people on a Yahoo group recommended a dentist's chair. If you do a search on eBay, you will find a variety of them, mostly under $100. Here is a link to the search I did:
http://www.ebay.com/sch/i.html?_from...chair&_sacat=0
Where I live, I doubt I could find anything locally like these options for under $100!