on average how much your SAAS generate per month

I'm a big fan of recurring income generated by an online tool you created on a weekend. We recently launched a SaaS, that generated 50k on one week using affiliates. it was a one-time fee, pricing model. I believe running a SaaS product on a one time fee is not a good idea, I'm willing to make my all upcoming SaaS products Monthly or Yearly.

Would love to know the average income your SaaS generates per month.