can someone please give this card a Name and appropriate cost:
[name], $?, Treasure-Duration(?)
+$2
When you gain this card, set it aside from your hand. You may spend it at any time during your Buy phase and is not discarded during Clean-up. When you spend it, trash the card and gain a Curse.
Let's clean up some stuff
1. This isn't a Duration. Durations stay in play, this gets set aside. So it's just a Treasure.
2. Change it to "Worth 2$". Just makes it a lot cleaner and shows that it is a Treasure and not an Action.
3. Axe the Curse clause. If this card had it, I would never get it, no matter what the cost.
4. Reword it to this:
"When you gain this, set it aside. At the beginning of any of your future Buy Phases, you may put this card into play. At the end of clean up, trash it."
5. This would probably cost
4$. It's similar to Mining Village as you buy it, and then the next time you play it, immediately trash it to boost yourself up to higher costing cards. This card has more flexibility (allowing you to have that +2$ whenever you want it), but doesn't have the dual purpose that Mining Village has of being a Village if you need it in an engine.
6. For the name, what about
Relic? You happen to find a Relic! You keep it safe and know you can use it to help your kingdom prosper when the time comes.
Overall, cool card! Never really thought of one quite like it.
Hope I helped!