Does the card provide a 1/N% chance of actually using plats and colonies, or 100% chance? If it's the former, than providing an amount of coin that competes with plat could be oppressively good in Province games.
Maybe you'd want something slow to get rolling to make it too much of an investment for Province games, so like
Scavenger Hunt
3$ Action
+1 Action, +1$.
Reveal cards from the top of your deck until you reveal a Scavenger Hunt and put that card into your hand. If you didn't reveal a Scavenger Hunt, +1 Buy. Discard the other revealed cards.
(There are forty Scavenger Hunts)
Also, LastFootnote is a major innovator and great designer of new Dominion cards, and a paragon of this forum