There's no point in paying for any kind of "training" software on a yearly basis. I don't know which video poker software is available for Macs, but they're pretty much all perfectly usable.
What you want is:
1. The ability to build custom paytables. Ideally, all (or at least most) of the most popular games are already in there, with the ability to change one or more payouts (so there might be 10/7 DB by default, which you can change to, say, 9/7).
2. The ability to generate a strategy chart from any paytable (and that chart should be arranged in a hierarchical decision order).
3. A practice function that you can assign any paytable (and associated strategy) to, that will allow you to switch from "warn me of all errors" to "keep track of cumulative errors and display them after my session is over."
4. The best software will calculate risk of ruin and bankroll requirements for you.
5. And of course, the return for each paytable you create, assuming optimal strategy.
If you have all that, there's no way you'd need an ongoing "subscription" to anything. There might be some games, such as Ultimate X and its variants, that aren't usable with conventional software, but otherwise, if you have software that does all of the above things, that should be good for 99.9% of all the games you want to play (and in a pinch, you can do without #4).