Additional Rules from the Rulebook
The card you gain is put into your Discard pile. It has to be a card from the Supply. You cannot use coins from Treasures or previous Actions (like the Market) to increase the cost of the card you may gain.
The Secret History of Workshop
In an article on Board Game Geek, Donald X. Vaccarino commented on the development of Workshop:
- The very first version of this card was "+1 Action. -1 Buy. Gain a card costing up to 3." Hey, "-1 Buy," what's up with that? I was trying to design a card explicitly for a moneyless deck. It worked too - once in a while. Most games it was unplayable. Everyone hated it but me. Eventually I relented and dropped the -1 Buy. That version was still too narrow and well you know what it looks like now.