My product NumeroMoney (https://www.numeromoney.com) is the first I've built that makes over $500, and it's grown surprisingly quickly. I built it because I needed something simpler that the existing solutions I could find for understanding our families spending (YNAB etc were geared too much towards budgeting). It helps users to import and categorize bank statement transactions in a way that makes it really easy to make decisions about household spending.