Target opponent exiles cards from the top of their library until they exile a nonland card. Until end of turn, you may cast that card without paying its mana cost.
5/1/2012 You cast the card from exile. Each land card exiled this way will remain exiled.
5/1/2012 If you can’t cast the nonland card (perhaps because there are no legal targets available) or if you choose not to cast it, it will remain exiled.
5/1/2012 You must follow the normal timing restrictions of the exiled card.
5/1/2012 If you cast a card “without paying its mana cost,” you can’t pay any alternative costs. You can pay additional costs, such as kicker costs. If the card has mandatory additional costs, you must pay those.
5/1/2012 If the card has in its mana cost, you must choose 0 as its value.
5/1/2012 If there are no nonland cards left in that library, the opponent will exile all cards from their library, and Stolen Goods will finish resolving.