I don't have bitcoins, but have paypal. Not looking to pay $500 on ebay, but someone with a decent price.
I have some, but wouldn't part with them for less than the value you listed sorry
Lets face it once bought they have very very low running costs, as such Roi can be high as difficulty raises wont make the power consumption a problem for a long time.
Also difficulty has been raising much slower than anyone would have guessed 6-12 months ago!
Myrdd