A day. Okay, it isn't quite that simple. My sideproject is Breaker 101, an online class for web security. (https://breaker101.com)

I launched on HN and sold out (75 seats or so, $1500 each IIRC) that same day. I had designed the syllabus over the previous couple days, but there was no product -- because I honestly thought that only a few people would buy it, and I'd just have to refund them.

I built the class over the next few months and that went really well (not perfectly, but definitely well), but subsequent runs never got anywhere near the same success in terms of sales -- just couldn't get it in front of enough people.

I recently relaunched it at $150 in more of a self-driven form. It's profitable by all means, but it needs marketing behind it. I've been thinking a lot about selling it to someone that can give it the love it needs, but I'm still on the fence there.