What are they for. You aren't going to get to shop any decent - elite or exceptional - as these are all going to be magic or unfindable in normal.
On the other hand, if you search bows and quality isn't an issue - to make edge for instance. Then you can already shop them from the start, or atleast form a very low level. You can get 3 socket long bows in act one. And as the ilvl are fixed in normal, you can shop them with any character.