I'd like to remind all the 'newer' (since its with them I notice/hear about this the most):
Just because obtaining X thing in RO took you Y hours, and you can make Z zeny per hour at hillwinds, that X is not worth Y*Z zeny.
I honestly do not care that it took you a 100 hours to get a cotton shirt and you can make 1 mil per hour at HW, I will not buy your cotton shirt for 100m, because that is not its goddamn price
!
2ndedit: Prices are based both on "Supply and Demand" (and if you don't know what that is google it, not the hardest economic term), and ease of kill (in RO's case).
The reason some cards are worth more than others, poring vs hillwind [Yea I love HW] for the sake of an example, is because poring cards are hatters, why are they hatters? because you don't significantly benefit from kill a hundred thousand porings, compared to if you killed a hundred thousand hillwinds.
Other slightly more useful cards like anubis are worth pretty much nothing because you can one shot them, whether you did or didn't one shot them, or whether or not it took you 10 hours vs 4 months doesn't raise its price.
So next time you're gonna vend anything think about how good the supply is, how many people want it, and how easy it is to theoretically obtain it.
Thanks
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edit: added emoticons
(I think I covered everything at least superficially, anything I'm wrong about feel free to correct me
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