The JuiceSSH app has been touted as being the "best free SSH client" available in the Google Play Store. But while the developer has made a commitment to provide a solid free offering, they do have a paid version available. In this case we are referring to JuiceSSH Pro, which brings some extra features.
Having said that, it looks like the app has reached a new milestone in terms of downloads, and as a result -- you can get the Pro version for free. The milestone is 500,000, and the offer will remain available until Tuesday March 18th (closing at 11:00 GMT). For those wondering about the value, JuiceSSH Pro regularly sells for (roughly) $7.00.
The offer appears rather simple to claim. You'll need to visit the JuiceSSH site (link below) and enter your email address. Make sure to enter the email you have associated with your Play Store account. From there is looks like you will be getting a lifetime license for an unlimited number of devices -- all tied to that Google email.
The details mention how you should get that code from an automated email in roughly 2-6 hours. All that having been said, some of those pro level features include a widget, the ability to sync and backup connections between devices, options for local, remote and dynamic (SOCKS) port forwarding, additional terminal color schemes, a security lock to automatically lock the app, and more.
The JuiceSSH app can be found in the Google Play Store, and otherwise, hit the link below for a full list of the feature set -- both free and paid.