Comment by XCSme

I built and run UXWizz (https://uxwizz.com), the revenue varies, but averages around $2k per month in a year.

It is not a service, but has one-time payments, so there is no stable MRR figure. It was initially sold through CodeCanyon, here's a graph with my earnings there: https://i.snipboard.io/7lubPE.jpg

Being a one-man-team, I tried to keep operation as simple as possible and automate the processes that could be automated.