I guess not the simplist once you get under the hood, but I've started two nice profitable SaaS products and just launched a third:
https://www.simplecrew.com - street team reporting/tracking tool (2012 - present) https://www.crewfire.com - social media brand ambassador platform (2014 - present) https://www.chainfuel.com - telegram analytics/anti-spam/management dashboard (beta release last week)