Where do you find e-books that are several times cheaper than paperback? Sometimes they're half the price, but often they aren't cheaper at all.

And that assumes you find a DRM free copy at all.

Ebooks go on sale a lot. You can often get them for less than $3.00, but it takes effort to track what you like and keep an eye out for sales. The trade off wasn't worth it for me years ago and I paid full price for what I wanted to read... lately there are very few books I pay full price for.