Another option, which doesn't require Adventures:
Decay (Action) $3
+1 Card
+1 Action
Trash a card. If you didn't trash a Copper, gain a Copper.
When you buy this, put the top 2 cards of one pile of Kingdom cards or the top 2 cards of the Curse pile into the trash.
Which is your fave between this and the −$1 token option?