The first trader is probably the one in the grove ? From memory, all the goodies you can pick up on the way there (Nautiloid wreck, Harper cache, goblin raiders) are sufficient to buy at least one magic item. The harper cache is easy to miss of course.
Close to where you find Astarion, you can jump down a cliff and find a chest hidden under a rock which contains some gold (I think) and a map to the Harper's cache.
