Did you send them the 0.005 BTC per item price suggestion ?
But serious numbers are 4000 usd divide by 180 = 22.22 usd a gh
so 1.6 x 22.22 = 35.55 would be the minimum possible.
I would think they can sell it at 50usd and make money. I would think I can buy them at 85 usd and make money on ebay and mining 50-50 mix. over 85 I lose interest.
If these work well They sell on ebay at under 200usd more like 140-175. Very short window at that price. Then a big drop.
so .1btc would be my max price
I wouldn't entertain that price, especially for re-selling. I'm not into ripping people off on eBay or anywhere.
I like to be honest and explain how much the devices I'm selling would make back, even if some buyers don't care or don't understand.
If they are over $50USD for a single miner just for a hobby to try out then I might go with that, but in bulk they'd have to be much much lower price.
If not, they can keep them and do the work them selves selling them on eBay ripping people off.
PS. Long live ASICminer, they are the kings of USB miners.