http://www.mandolincafe.com/
well i looked up the Gilchrist mentioned on the mandolin cafe
and it is 16,000 so you probaly want to look furth3er!!
There are 48 mando family instruments listed at ELDERLY
several under $1,000, a few under $500.

good luck. I have a Weymann Mandolute, and am quite happy with it,

My friend Larry at http://www.thinmanmusic.com in the S.F. East Bay Area has one for sale here:
http://www.thinmanmusic.com/mandolins%20&%20mandolas.htm
http://www.thinmanmusic.com/mandolinpics.htm
http://www.thinmanmusic.com/mandolins,Mandolas,octave%20mandolins,%20bouzouki.htm