Installed this and then found that I am required to pay an annual fee to learn how to use it. Really?
If a plugin is made available like this - make it clear that any documentation is to be paid for. I have no problem with that - I do have a problem with something that encourages you to install then requires payment.
Just be upfront and make it clear that to get the best from this 'free' plugin, payment is required for the documentation.