If you own and travel with a laptop computer you can begin reading EBooks without any additional expense. 

You do not have to buy an EBook reader, just download Kindle for PC of Mac, for FREE. It will probably come with several free books to get you started. Personally i am happy to pay for a good book, my main interest in downloading EBooks is that it will reduce the weight in our car and caravan and frankly I find them easy to read. Easier in fact than those tacky yellow paged paperbacks you are most likely to find in book exchange.

After that, just put in a search for $0.00 books and you will find lots of free books.  Please respect the copyright of authors and deal only with those companies who publish books available under a public domain licensing and have been converted into e-books. There are over 1,000 license-free titles in the Creative Commons license EBooks and you can find them in these websites:

• Many Books
• Open Library
• Project Gutenberg
• Google Books

As an avid reader and fussy about the choice of books I read, I was never happy to just select from a book exchange at caravan parks,  I had been traveling with a library of reference and fiction books. Having discovered EBooks, this has changed.