Freeflow - Metered Content
Freeflow allows you to give your visitors a sampling of your paid subscription content on a per device basis. It takes the device fingerprint of your visitors and keeps a record of them for you. When the visits are exhausted they are redirected to your Paywall.
Freeflow adds a user to the right user group and view access level for the content you want to show off. It does this only for the current page and stops doing so, when the hit count for your users device reaches the limit.
The messaging is completely customizable via template, and the admin. It's a snap!