To solve the supply problem I would add a "When you trash this card, return it to the supply." Maybe add "instead" at the end and "would" before trash, but Trader has wording issues and have the card visit the thrash before going back to the supply should be no problem. In any case, you get the idea.
You should also limit what you can put in your hand to non-Searchers, otherwise the limit is just non important, because you can put the next Searcher in your hand and start over.
The searching seems quite strong, especially with cursers. I would price it at 4 so you cannot open Searcher/Sea Hag or Searcher/Young Witch. In any case, besides the opening, the pricing would probably be no big deal because you mostly will buy one of these and just gain more with it if you need.
Final comment, stacking the effect with KC can set up combos like KC + Scheme + Golem + X without needing a third enabling card.