I found a set of Dura-Ace 7800 pedals on eBay for less than 60. Or about the same price as a new set of 105s.

Any good?

I also found a bunch of Ultegra for ~30.

So are used pedals worth it? Or should I just bite the bullet and get a new one? All the sellers say they are in good condition (obviously). Why do people sell old pedals then?