Well I wouldn't sell a Key Lime for 500euros, not yet anyway - perhaps in a few years time depending on the market.
For those who wish to pay 500euros at the moment, I don't think that's crazy. People who will readily pay that are obviously happy to do so, and there's nothing wrong with that.
In a previous thread I showed photos of a near-mint,
boxed G4 iBook I purchased earlier this year. I didn't mention a price, but if I admit now that it wasn't far off 100euros, many would think I'm a madman. If so i'll willingly wear my straight-jacket with pride; to me that iBook was worth every penny. And for those who think it's trash, that's ok too.