With the release of Start8, we have introduced the purchasing option for the full non-trial version.  Whether you have a new purchase to activate, or are reinstalling you will be prompted upon starting Start8 to either try the trial version, purchase, or unlock the app.

If you have purchased Start8, or are an Object Desktop subscriber than click the ‘Unlock previous purchase’ button.  You’ll then get another window asking for your Stardock account info, and after you enter that and hit login you will have activated the full version of Start8.