This is one of the best epic Saviors of Uldum cards.
This card can easily turn into a very productive draw engine in the new Quest Druid deck. All you need for it to work is to keep one mana unspent every turn, which is basically what you pay to draw that one card.
Think of it as Acolyte of Pain where you pay one life for a card. However, Acolyte has only three life, while you can exploit Crystal Merchant's ability as long as the game goes on.