I bought some cheap $25 window motors off ebay. They were built in the USA though, and did come with a lifetime warranty. One of them (I replaced both windows in 1 F-body, then 1 on my Z, and two more on a 3rd F-body I later got) in my 3rd F-body (the Formula in my sig) eventually went bad. I ended up just getting another $25 cheepo off ebay and didn't even bother trying to find the paperwork for the warrenty. So far all the others have worked well, and I DD the Formula.
Heres a link to a similar one on ebay>
http://cgi.ebay.com/ebaymotors/1985-...Q5fAccessories
FWIW though, if you want a quality one that will last longer and you don't have to worry about going out as often I would reccomend getting a more top notch window motor. The factory GM ones are junk, but there are others that are better.
Something else you might be interested in is this>
http://www.autotrix.net/Product-Driv...own-Kit_8.aspx
Never tried it personally, but I have seen videos of people who have and it looks pretty sweet!