That was an interesting effort. The subscription platform for SlideMagic has now been put in place. Given that many payment platforms are not available in Israel (a tiny end user market that is a low priority for most tech companies), I have incorporated in The Netherlands, and integrated a subscription payment platform, a subscription app, and a pricing app into my store platform. The result: you can now subscribe to SlideMagic, after which all prices in the template store drop to zero when you log in (no more discount codes to enter), and you manage all your address details, credit cards, invoices, (and yes cancel your subscription) from a panel that is integrated into my site.
It is incredible that in 2018, a 1-person operation can pull this of, a few years ago this would have required a very substantial development team. I will continue to focus on developing the content of the SlideMagic store (which makes it unique versus the 1000s of cosmetics-only templates that are out there) while I monitor how the technology is holding up, keeping marketing efforts modest at the moment.
If you want you can still join the beta subscription program for $100 by going to the subscription page.