Well, I imagine it's set up like iTunes is. You sign up for the service, then purchase the individual programs on the fly. For the subscription service, I would tie it into the person's lifestyle. I'd restrict access to Knowsofts to Low or better lifestyles, while Activesofts would only be available to Medium or better. They would also require a decent SIN (R4 for Knowsofts/R5 for Activesofts?).
I'd probably offer a 10-25% discount on Skillsofts for subscribers. Depending, of course, on the skill.