I would say it depends on the quality and craftsmanship of the bow. I have paid 150 for a bamboo backed osage and thought I got screwed, I also paid 500 for a bamboo backed yew and thought it was a steal. Test the waters, put an asking price of 2-300, if they sell like hot cakes, you may want to raise the price some, if they don't, you can lower it some.
You also need to prepare yourself before you start selling bows. Some people will never be happy no matter what you do and that can be hard to take when you are talking about something you made by hand.