Based on the resource accumulation spaces of Agricola:
Others have already stated it, but this is a nice, clean and simple design. I have not played Agricola so I am not familiar with how this mechanic works there, but in Dominion it may need a few tweaks to address some issues.
Here are my concerns:
(1) The opportunity cost does not seem high enough. When setting the price at $3, there is always going to be a number of Coins in the pile that makes that price worth taking it. Depending on the number of players, that magic number may always land on your turns or worse, your opponents. You could make the choice to take the token pile a lot harder by making a Curse gain the condition, similar to Defiled Shrine.
(2) I mentioned this briefly already, but the number of players will drastically alter how this plays. In a 6 player game, some players may never have a shot at getting a decent pile of Coins. You could make this scale less with more players or change what adds tokens all together.
I realize most of the ideas for these competitions are developed on the fly and are going to have issues that maybe are not worth fussing over (my cards certainly apply), but man this is a cool idea and I'd love to see it fleshed out. Thanks for sharing!