Just a further comment about returns with a website I recently bought from: www.booklocker.com
They sell e-books without a return policy. Actually it is there, but loosely defined in a pleasant, user-friendly sort of way. This is the first site I've seen that actively discourages returns, but I don't know how it affects their business.
Here's what they say in their FAQ:
"...Q.What if I buy an eBook but decide I don't want it?
A. Since eBooks are electronic and not "returnable", we do not issue refunds except in the case of an order incorrectly filled or when a customer truly can't open and read the ebook they purchased. If a customer spends several hours at their computer and still can't figure it out (hey, we're not all techno-geeks), we're happy to refund their money."...
This site is well designed and gives a good feel about buying e-books from them. Worth a look.