I originally built OnlineOrNot (<a href="https://onlineornot.com" rel="nofollow">https://onlineornot.com</a>) with the expectation that no one would use it, using 100% serverless compute that would cost me nothing when unused.<p>I was a consultant at the time, and wanted to point out how crappy my client's webhosting was (really I just wanted to convince them they were going offline long enough that spending an extra $50 per month on a proper wordpress host would actually make them money)<p>I kept a twitter thread of all the features I was adding (<a href="https://twitter.com/RozenMD/status/1364881512500404224" rel="nofollow">https://twitter.com/RozenMD/status/1364881512500404224</a>), and eventually it spread via word of mouth. It doesn't make life-changing money, but I could see myself running the service full time eventually.<p>I ended up moving off of 100% serverless compute, since enough people were using it constantly that it was 80% cheaper to run several servers 24/7.
I made a mobile game several years ago that brings in $100-200 per month: <a href="https://apps.apple.com/us/app/card-crusade/id1383938095" rel="nofollow">https://apps.apple.com/us/app/card-crusade/id1383938095</a><p>Took a few hundred hours to implement, we got pretty lucky to find an audience, and it’s too a year or two after making it free to actually start getting recommended by the App Store - I think we must’ve crossed some threshold for getting enough positive reviews, or something. Anyways, I can’t say it’s a reliable way to make money, but I had fun doing it, and it does bring in some money.
We’ve seen some moderate success with Smores - <a href="https://www.smoresmusic.com/" rel="nofollow">https://www.smoresmusic.com/</a><p>Brings in about $100 MRR split between 2 people.
I built YCRM (<a href="https://ycrm.xyz/" rel="nofollow">https://ycrm.xyz/</a>) as a tool to help me get in touch with YC founders for user research to validate B2B SaaS ideas!<p>It's been surprisingly successful with other B2B startups.<p>Not enough revenue to be my main source of income, but it's a nice monthly bonus.