Seriously, what the hell?

Sometimes gamers can be very odd. In 2004, when Nintendo released the NES Classics line for the Gameboy Advance, people complained because Nintendo was charging twenty bucks for what were essentially emulated versions of NES titles. Fast forward to 2006, and on eBay people are paying up to 30-40 dollars for a used copy of Super Mario Bros. Oddly enough, the other NES Classics titles, like Zelda and Metroid, only seem to be going for around ten, fifteen dollars at the most.