The Amazon Kindle Lending Library is quite a perk for Prime subscribers: a free book rental every month. This, along with the free streaming video they added a little while back makes Prime even more compelling.

Amazon’s not dumb, they know when people sign up for Prime they stop shopping elsewhere. Any perk that gets people to sign up for Prime is a big win for Amazon. However, the lending library has another, more subtle, twist to it.

My wife and I each have a Kindle and both Kindles are connected to a single Amazon (Prime) account. With the Lending Library we can only have one rented book out at a time (you have to return the previous one before you rent the next one). If we were reading one book a month for free, that would be a savings of ~$120/year. A second Prime membership costs only $80/year.

You can see how this feature will incent some families to add another Prime membership.

Once you have your Kindle set up on your own Prime membership, that is also the account where your new book purchases will go – each person will have their own book library. It perpetuates the need to maintain the separate account.

Is the Lending Library a great perk for Prime customers? Absolutely. Will it also benefit Amazon? Of course. And on several fronts.