From DominionStrategy Wiki
The first time you play a Silver this turn, + .
 Official FAQ
- When you play Merchant, you draw a card and get +1 Action.
- If you end up playing a Silver later in the turn, it comes with + .
- If you play more than one Merchant, each gives you + when you play that first Silver; but if you play more than one Silver, you only get the + for the first Silver.
 Other Rules clarifications
- If you manage to play a Merchant after playing a Silver, the Merchant gives you no bonus (for the previous Silver or for any Silvers you might play later in the turn).
- Playing Throne Room on Merchant will give you + when you play your first Silver.
- Storyteller, Villa, and Black Market can make it possible to play merchants after you play your first silver, which won't get you any extra money.
 In other languages
- German: Händlerin (Note: explicitly feminine)
- Russian: Купец (pron. kupyets)
 Secret Historyon having an Action in play (and another version that wanted an Action in hand), and that was nice, but I didn't want something too much like