We got trial keys about 5 years ago added to our MBS FileMaker Plugin.
A trial key is only valid for a limit time and allows to test all features without demo limitations. Due to the time limitation of the key, you can use it for a few weeks. The key later expires and you are back to demo mode or you order a license to get a permanent license.
We setup a form to request a license key:
Request Trial License Key
We may limit who can get a trial and filter out the requests looking like spam. But so far we issued over 1000 trial keys to various people.
Please understand that trial keys are not intended for deployment of solutions as keys expire. Our regular keys don't expire and can be used forever with the plugin versions released before a given date.
You can also explicit register for newsletter, so you know about new releases and events.