Originally posted by Aristophanes 
He's also trying to trade for a more appropriate lens to his needs, like the DA 35 Macro.
This is just a market functioning like a market.
I am not sure where the product for prizes originates, but a gift certificate from commercial site sponsors may be another idea.
Was going to say about the same thing myself. Everyone can spend a gift card and get exactly what they want - promoting the site sponsors would be a secondary benefit to them as well (and they would probably kick in some extra funds in the process making it more enticing to everyone).
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