Solo dev here. Shipped my first app a few weeks ago (a daily Stoic quotes app) and have been grinding marketing every day with $0 to show for it. Today I went for a run. Came back, checked my phone — and there it was. My first transaction ever. Someone bought the Lifetime unlock while I was out running. I know one sale isn't validation. But a stranger on the other side of the planet paid for something I built alone in my room. I've been smiling like an idiot for an hour. Keep shipping. (...