People do let them go for around $300-$400, on ebay $400-$600. There almost on the edge of their life span so the ROI is long or not there at all. 1.6Th/sec @ 2000W means if you pay .09 per Kwh you will never get your money back out of them given current diff increases.
I would offer you about the same $300 and I will provide shipping labels is my best offer.