In the world of Heroes of Might and Magic powerful artifacts are a (relatively) common quest reward. And by "powerful" I mean powerful, something that can turn a would-be catastrophic defeat into a glorious victory. However, I cannot really make a good justification for such rewards. Why would one even consider selling such a powerful item and not, for example, found a small kingdom or at least a gang to rob everyone around?
My specific problem is justifying someone selling a powerful item for anything. I want to create a trader that doesn't seem stupid, while still making the price realistic.
I don't want players to think "Oh, wow, that guy is really ready to trade a few useless units I have for a Relic-tier artifact!", but neither do I want them to completely ignore the quest/offer due to very high price.