Help! LMS for non profit- no cost or low cost?? No tech team!

Good afternoon! My small two-man non-profit has spent the past year creating a Learning Course on Kids Brains & Screens for parents that we are going to roll out to a local private school ASAP before going larger to a local school district and then to a much larger audience after that. The course will be available for purchase and includes 16 lessons that we would like the end user to be able to track and save their progress as they move through the course, potentially adding quizzes to our content down the road. We would also like to track the progress of the participants and glean data for the schools that purchase the right for parents to take the course. It would be helpful for the software to be able to generate unique one time access codes rather than a batch approach (for example, we have a donor that has paid for a school to get 100 access codes to the material that we don't want shared outside of that school community). A third need is that individual parents would be able to purchase the course at full cost and have access to it for a lifetime. Can some community members chime in and get us started in the right direction? We have used Rise 360 to create the Course and were recommended to subscribe to Memberpress for the purchasing and management but it doesn't seem to be compatible with Rise 360 to host the course. Rise.com is way out of our budget. Please help!