Seems pretty weak to me. Playing this probably means not buying anything that turn anyway, so it's only useful if you have three Treasure cards but less than $8 or whatever the card you gain costs, probably $6-8. And then it will 8 times make you lose at least $1 (Potion and HoP aside), while it misses the reshuffle multiple times. So if you're gaining Provinces, you're gaining about $4 or $5 of value when you play this in the early game, $2-4 in the mid game and nothing in the late game, and losing at least $8 afterwards. Therefore, at best, you're losing only $3.
The idea is cool though. I think it should just gain up to $8 and place the tokens without discarding any Treasures when you play it, wouldn't probably break games. You could have something like "worth -1VP for each coin token on this card at the end of the game" if gaining Provinces in the end game is too strong.