OP neglects to mention if there were any back taxes or water liens owed. Or if the house had been condemned. All I could find was one lot (not house) under 8K.
http://www.zillow.com/homes/for_sale/Jamestown-NY/pmf,pf_pt/...
http://www.zillow.com/homes/for_sale/Jamestown-NY/pmf,pf_pt/...
I was having a look at another cheap house from around the area. Just check out the graph: http://www.zillow.com/homedetails/23-Barrett-Ave-Jamestown-N...
I'll agree though - the main thrust that Jamestown, NY RE is surprisingly low compared to elsewhere is an interesting one.
Sold on 8/16/11: $3,955
There are multiple houses that were sold below $4K there.
You probably forgot to turn on "recently sold" filter on Zillow.
http://www.zillow.com/homes/for_sale/Jamestown-NY/pmf,pf_pt/...