$15 is a fair price to me. i recently saw a small quilted wallet selling for 9. after looking at it i realized i had the same pattern at home so i dug it out and made one. While it was not difficult or time consuming, if I was going to make them to sell i would want more than the $9 they were being sold for.
Ask yourself if you really want to turn your fun into a job. If you are considering doing this, I would do as someone suggested and make some up and then offer them for sale. Custom orders can be a real pain.