Amazon has it on Kindle for $11.99.
Barnes and Noble as it on Nook for $10.21
If you use Android:
You might also check out Google Play. They have the book for $9.99. From Google Play you can also download a book to your PC.
Good sources for free ebooks are Google Books and Project Gutenberg.
http://books.google.com/http://www.gutenberg.org/For example Gutenberg has 62 of Kipling's books available, all free.
Calibre is a free program that will convert between many ebook formats and also remove DRM.
http://calibre-ebook.com/Depending on your local library, there are many good ebooks available.
Pete