The usual price for a used book on Amazon is $.01, which with shipping comes out to still far less than the ebook.
There are other good sources of free books include this blog: http://www.sfsignal.com/archives/category/books/free-fiction...
Losing the sync ability basically killed the main utility I get from eBooks. If I have to carry the Kindle around, I can carry a library book around.
It's sort of a hidden link or a special way of narrowing search results with the criteria on the left side of the page. If you google I'm sure you can find instructions.
In the search box on the main amazon.com page, there's a drop-down list on the left hand side of the text entry. Click that and change it to "Books". Now just hit search (you can leave the text field blank). That will bring up a search results screen with a bunch of filter groups on the left. Scroll down and select "Kindle Edition" under "Format". After the page reloads, scroll down even further and you'll have a checkbox for "Prime Eligible". Select that, and you'll have only the books you can rent with Prime. You can then further refine by genre, search term, whatever.
The selection is generally pretty awful though.
I don't like losing access to things. If it was "you can download one per month and keep access as long as you're a subscriber" sort of the way Playstation Plus works that would be OK with me.
But the rental program feels more like a cruddy crippled library than a real service.
I'd rather pay the $5-$10 for the eBook and not have to deal with it.
This new service is interesting. I don't read enough for it to be useful, but I could see it saving my dad quite a bit of money (or trips to the library) if they had enough books.
An appropriate term to use in a discussion that's literally about different media for books.