Dominion: Stash Promo Card [Board Game Link]

Released in February 2010 in Germany.

Text:
Stash (Treasure - Cost 5 [coin])
2 [coin]
When you shuffle this, you may put this anywhere in your deck.

Revised text (2017)
Stash (Treasure - Cost 5 [coin])
2 [coin
When shuffling this, you may look through your remaining deck, and may put this anywhere in the shuffled cards.

Part of the Dominion series.