I must respectfully disagree with Leo Babuta’s description of Kindle and iPad as “marketing devices” that drive their owners to purchase content. In my experience, some of the best content on these devices costs nothing.
Those with a bit of technical know-how can use their Kindles to follow RSS feeds for free on Google Reader. I was able to do it in 2009-2010 through the experimental web browser on the Kindle 3G, but it looks like there’s a few more free ways to sync Google Reader with Kindles these days. iPad owners can read RSS feeds in a visually beautiful way through the free Flipboard app.
Kindle and iPad owners can also download and read free out-of-copyright books from ManyBooks or the Kindle store itself. The works of H.G. Wells, George MacDonald, Edgar Rice Burroughs and Mark Twain are good examples. Vampire fans might also enjoy Dracula and Carmilla.
I do purchase digital books and comics for my devices, but that’s my personal choice and not one made for me by the devices themselves. The Internet is a bottomless basket of free content, and Kindle and iPad owners can go a long, long way on that free content alone.