Hola! Patrick here - Founder of PriceIntel/ProfitWell. Why ProfitWell is free is actually a longer story, but the short answer is we discovered we could monetize more effectively (and efficiently) by giving away the metrics for free (while still being the only one on the market that's 100% accurate) and then selling add-ons like Retain (kills your delinquent churn), Recognized (Revenue Recognition), etc.
If you're curious around the science/data that went into this (the longer story), you can check out a talk I gave at our SaaSFest conference: https://pi.wistia.com/medias/jdywlrpowl. We used our Price Intelligently software to determine market willingness to pay/feature value before writing too much code.
As always, let me know if you have any questions. Happy to help.