If you are planning to sell your book at places other than bookstores, you might want to consider a portable display banner to attract attention. Lightweight, retractable banners are widely available and with designs printed in full colour at high resolution, they can be quite striking. Prices are low and preparation of artwork (a service offered by WorkingType) is usually similarly inexpensive. The banner shown below this post features "The Sunny Side of the Street" by Maria Stefanidis.