built a saas tool in february. gave it away completely free. no trial, no credit card wall, no “upgrade to continue” popup. just free. for 4 months i watched people sign up, build stuff, and use it without paying anything. 170 users across 17 countries. zero revenue. then yesterday someone upgraded to pro. 12 euros. thats it. thats the revenue. she found the tool through chatgpt 14 days ago. signed up, started using it immediately. tried to pay on day 6 but her bank blocked the 3d secure a...