I think your prices are reasonable, depending on your area. I did some craft fairs a couple of years ago and found out talking to people that prices vary a lot according to your city and state, rural, big city, etc.
Here is a link to another cute, quick item to sell. Post it note holders. This gal Kerry whose blog I follow has a good tutorial and lots of pictures. She is very successful at shows and also has an Etsy shop:
Quick Video Tutorial: Post-It Note Holders
Here's a link to the home page of her blog, which also has some post it holders. Scroll down past the pictures of her darling new baby girl Brooke to see the note holders.
Kerry's Paper Crafts