I second the price increase idea - or perhaps another tier for usage. Ideally the free tier should be enough for a very casual users, or enough to test, but onc

I second the price increase idea - or perhaps another tier for usage. Ideally the free tier should be enough for a very casual users, or enough to test, but once they get serious they are incentivized to purchase something. You could try doing a timed trial too - 30 day for free usage perhaps. As others have mentioned I wouldn't worry too much if you need to lower prices in the future - as long as you reduce the monthly fee that your older customers get I am sure they will be happy. Also what kind of marketing are you doing? Often with projects that one is passionate about the drive is to build more features as opposed to build a user base. I think your product is developed enough feature-wise (I am certainly looking forward to trying it now that I have heard of it), and so I wonder what you are doing to build your user base. Off the top of my head I would suggest talking to people in language learning forums & communities, creating a newsletters / reminders to keep your existing users engaged, and possibly running targeted advertisements if you haven't already.