Why not just do one-time affiliate commissions if they're higher per sale?
One-time commissions plateau immediately. You make $100 per referral, get 10 referrals, then have to find 10 new people next month—your effort multiplies while income stays flat. Recurring commissions mean you earn $50/month from referral #1, $50/month from referral #2, etc. After 12 months of consistent referrals, you have $600/month coming in from people you referred 6+ months ago. The math compounds.