I don't believe anyone within their right mind will be selling their ASIC devices right now, aside from a huge markup, since bitcoin mining profitability is increasing rapidly, especially with exchange rates breaking $1000.
Expect to pay ~$60 per GH.
Yea, I had an ebay listing for my Klondike K16's each set at $300 and they almost all sold out in seconds after the first buyer, ended up selling 3 then cancelled the other 5, those 5 made me over $800 since then. I Have 5 Klondike K16's hashing at 5.5-8gh/s for sale in Pennsylvania, Difficulty is slowing down, so these should be profitable through Feb-March. If your interested PM me an offer