Full support for this idea. I've looked through your shop before and was quite discouraged by page 50 or so. This is not to say you have a bad shop, not at all, this is just to say that it'd be much easier to find the pet I was looking for if it was alphabetized.
I don't know as much about the pricing part, as it's never an issue for me, but I agree with it from the sound of it. After all, merchant shops are alphabetized, why not rancher ones.
Also, it might be easier if more pets were shown per page, but that's just a little addition to idea, not as important as the 0 tu pets and the alphabetized pets ideas.