I cold emailed a blogger that I learnt a lot from and showed him my app. He liked it, mentioned it, asked a friend with lots of followers to link it. Then it spread by word of mouth, and a few weeks later I had 1000 beta testers.
Converting beta testers to paid users took a long time, but eventually it became a profitable business.
If you make something people want, it's easy and you need very little marketing.
replies(1):