Well you could just skip those. You don't have to pay them if you
don't want, just like you don't have to accept Gem Exchanges like 1
Dark Gem for 2 Fire Gems. If you don't like the trade, just don't
do it.
I support this, it would make more sense. While it's true that you
can just skip them, why get the same amount of DP for harder to
obtain gems? That doesn't seem right, to me. Are a Dark Gem and a
Normal Gem really worth the same to that guy? He must've never
hunted them himself, before. He just cons people out of their gems
without noting the real values. XD