Why can't I try it?

[Ramana Seerapu]

I tried installing this add-on twice already in the last few days, and it tells me I don't have a valid license.

I would like to know if it's possible to try it before I purchase it.

Thank you,

-Miguel S. 

[Nicolas Bourdages]

Pretty much all plugins have 30-day free trials. After you get the plugin from the UPM, you're asked to enter credentials to get an evaluation licence. If that doesn't work for you, I suggest you contact the plugin's maker directly.