A Fantasy Hero GM of mine once introduced something from an old story/Twilight Zone episode. Each of the PCs encountered a mysterious stranger carrying a box with a red button on top. Press the button, and you gain fantastic wealth, but someone you don't know dies.
One player went for it; a down-on-her-luck royal antsy to get back her wealth/status/etc. To the surprise of some, she did indeed come upon a great deal of money. To the surprise of no one, the stranger moved on, after declaring his intent to strike other bargains "with someone you don't know".
In game terms, that meant the GM made a roll (probably Luck, but I don't know) every game month until the player's number came up. We told the player later that every time we used the quality gear she (indirectly) bought for us, we were paying tribute to the character. I don't think she bought it.