[dlehman]

It is indeed $19.99 here in Canada.

While a one-time fee seems preferable from a customer-standpoint, I personally prefer annual subscription fees. It allows for a potentially lower initial cost, making it more accessible to potential customers, but--more importantly--provides an obvious recurring revenue model for the author, hopefully implying on-going development. Ideally you would retain access to the app if your annual subscription lapses, but could receive upgrades after reviving your subscription. Whenever there is a one-time fee for an "average" app (no offense intended), I always wonder how the author can afford to keep updating it in the future.

[xenodium]

Thank you. This is encouraging to hear from a potential user. There may be a middle ground where new features are sold separately (specially feature requests). Having said that, everything you get today with v1 will remain covered by what you paid for the app. No rug-pulling ever to force folks into a subscription.

[lycopodiopsida]

It is how Beorg does it - they have a subscription covering everything, but users can also buy singe features. However, I imagine that at some point the coding will get quite complex - developer has to build a couple of feature toggles and ensure that they work well in every imaginable combination.