How much would y'all pay for a PF85?
http://www.yamaha.com/yamahavgn/CDA/ContentDetail/ModelSeriesDetail/0,,CNTID%25253D176%252526CTID%25253D205800%252526CNTYP%25253DPRODUCT,00.html
It's well used with some scratches but still seems to play fine. There are three currently on craigslist: $550, $350, $300. But the HC user review has one listed as bought for $210 in 2005. That seems like a wide range of prices.
This will be used by novices so as long as it is mechanically/electrically and the price is right it'll be just fine.