I am sure this topic will come up anyway very soon, so let me be the one to start it:
I am a happy GarageSale user since 2006. I use it daily, and it has helped me a lot to build and successfully run a commercial business focused on eBay. So, I am definitely right there in the target group you mention.
I also have a background in software development, so I fully understand your needs, the effort it requires to not only build, but support a piece of software and continuous releases, and that you need a somewhat predictable way of income to secure further development.
I am, like many others, not a big fan of software subscription, though. I understand and accept that it can make sense in certain scenarios, but I find it a matter of respect towards clients to offer it as a choice. The moment I feel blackmailed into a subscription, I am out… and my understanding is that I am not alone with this attitude.
Let me repeat: I do understand your needs to change to a more predictable income. Or higher income per license, especially from commercial users. And I would be more than happy to support future development as well as current support by buying a Pro license that is priced higher than the basic or current version of GS, if you give me that choice. Right now, all you offer is: license, but only up to 50 listings per month. That wouldn’t work for me (I am above that level). Or, buy the subscription… which I don’t want. That’s why I feel blackmailed. A piece of software, that I use daily, and love to use, suddenly no longer offers me a license model to feel comfortable with.
That’s why I am an ex-Adobe user, an ex-Ulysses user, an ex-TextExpander user and likely an ex-1Password user soon. I am still a CaptureOne user and an Office 365 subscriber, because those two offer me a choice (and regarding MS Office the subscription made sense in my case… I am not a subscription hater per se).
Please don’t make me an ex-GarageSale user and reconsider your licensing options. Personally, I’d love to see a Pro version that can be licensed in the ‘traditional’ way, even if it comes with restrictions or limitations compared to the Pro subscription. I, personally, wouldn’t expect free upgrades with it, or syncing, because I understand that this creates continuous costs on your side to run the additional servers. But then please load the costs for that onto the clients that actually want and use the service.