Okay, we're getting quite off-topic here. But that's okay, right? 🙂
I wrote a long time ago that charging a low monthly fee can be a good approach. It absolutely mustn't scare off potential customers.
It's (nowadays) very important to reach small retailers/shops that don't have a large budget.
This is exactly where Thirtybees would be a great solution, and $4-5 per month for the shop as pure software would be fantastic. Payable every six months in advance.
If that's too complicated to implement, offer a free 30-day trial or something similar. Then the license would need to be activated.
It's important that no money-grubbing third-party provider does this (no Envato, please).
And of course, it has to work flawlessly. I'd be happy to receive a license via email and have me insert it into a config file and upload it—no problem.
I'm fine with that. In addition, there could be paid premium modules for ThirtyBees (as has already begun).
That's fair, because nowadays it's also important to only pay for what you need.
One more important point:
Some information about ThirtyBees is extremely outdated. The demo, changelog, version roadmap, etc.
It's also not entirely clear how and for what purpose paid support is provided; this urgently needs to be revised.