Do you have a library card? If so, it is very likely that your library supports digital book lending. It works a lot like checking out a regular library book. The library has a limited number of titles they have the right to “check-out.” If you are trying to check out a book that is very popular or a new release, the waiting list may be long (I've seen the number into the 50’s), however once it becomes available the library sends you an email letting you know it is available, and then you go to the website and download the book onto your e-reader. Then you have the book available for you to read, usually for 7-21 days depending on your library’s lending rules.
In a lot of ways, this is better than searching through the 1000’s of free titles available on Amazon because you now have access to a lot of the better known authors. The flip side of this is, if there are lesser known authors you are a fan of, they probably are not available digitally through your library and you’ll still have to buy those books. My thought is, I’d rather help the little guy out by paying for their stuff rather than George R.R. Martin or Dan Brown who have sold millions of books anyway.
This is also a good way to read some authors you've always thought about reading, but are popular enough that the cost commitment to buying a full book is just too much. Much like the free books on Amazon, you can read a book and if you love it, either check out another by that author or go and buy it now that you know you like the authors writing style. If you hate it, you just return it and you've lost nothing but the time you spent reading it.
So why am I writing about this? Honestly it is because I’m constantly amazed at how many people do not know about this. Nearly everyone I know has an e-reader, but almost none of them use this service. It’s free! I don’t understand why someone wouldn't go with free! So go out and dust off your library card and log-in to your local library’s website to check this out! I promise you won’t be disappointed!