Amazon has just started sending exclusive invitations to select customers via email, asking them to try the Kindle Fire HDX for 30 of charge.

The invite seems to push the standard Kindle Fire HDX, but customers can also choose the Kindle Paperwhite 3D, Kindle Fire HD or the Kindle Fire HDX 8.9-inch. With this program, Amazon likely wants to hook customers on to the Kindle line - especially now that the Christmas shopping season is upon us.

"Kindle Fire and Kindle Fire HDX are a brand new generation of powerhouse tablets, built for work and play. But instead of simply telling you all about them, we'd like you to experience one for yourself, risk-free for 30 days," Amazon says in the invitation.

The trial has a limit of one per customer, while supplies last. Amazon clarified that it would ship the eReader to customers at no cost, and it would only charge a customer if the eReader was not returned after the trial ends. When it's time to send back the eReader, if you decide not to keep it, Amazon will cover the return shipping as well.

We've contacted Amazon for more details on the programme, such as whether it is US-only, exclusive to Prime members, open to anyone with an invitation, etc. We'll update when more information becomes available.