A reseller typically purchases the SaaS at a discounted price and bill their client directly.

I've seen reseller discounts range between 10% and 50%. The discount should be competitive with your industry, and allow a reasonable ROI for resellers. The reseller discount is typically for the life of the user otherwise expect resellers to offer their clients a competitor's SaaS.

An affiliate or partner program that pays a commission for referring clients creates a direct relationship between your company and the users. In these types of programs, your commission could be a one-time payout upon referral, a recurring % of sale for the first year, or a recurring % of sale for the life of the client.