2. Google Books
If you have Google account, you can see that this company has designed a tool to read books. It enables access to a huge collection of english books online. It was really titanic work to scan and turned them into viewable files. is now available on Google. Here all the books are free but the the thing is that some of them are available in the form of a free sample and some in full size.
The limit of free pages is set by publisher. It may be 20% or more and reader is allowed to chose where they should start, in the beginning, in the middle or just consist of random pages.
Also, Google Play, another Google online store, offers their e-books at a set price.