To answer your question, we have quite a bit of original content and functionality beyond the book lists and transcripts. And based on my experience assembling customized homeschooling curricula for my kids, the book curation in itself is a major value add. If it saves the parent just a few hours of research time, or connects the student with just a few resources beyond what parents could find on their own, it would be worth the cost for many families.
The main differentiator in a homeschooling curriculum is what the student will spend his/her time doing and reading, and optimizing this seems like it would be worth paying for a service rather than relying on free book lists from the internet. That's our hypothesis, anyway.
Maybe consider regional pricing? If you include this and region specific books as well, your service will be golden.
Btw, what stops someone from paying for just a month or two and collating all your plans and then use it for the rest of their lives without paying you anymore? I mean this genuinely and not with ill intent.
Regarding pricing, I'd be happy to pay an amount as one time purchase for the entire curriculum vs a subscription model. Or pay one time for each bundle/grade. Just some ideas.
Super bonus points if you can record a couple of the lessons being delivered and post them on Youtube or whatever—the more you can convince prospects that they can use this and have it actually work, the better, I'd expect, and videos can help fill in gaps in imagination or confidence in turning written materials into a real lesson. Kinda like how sometimes a YouTube video of a board game with complex rules being played can make one more certain about how to run it, than reading the rules a couple times.