I crossed 300$ in revenue after 2 months

I crossed 300$ of revenue in just two months for a free product. My mind is blown. I'm surprised and I don't understand. But it seems it was a good decision to provide the app via Gumroad for free, with an option to pay. People have. And it feels good.

I did some advertising on a deals site to promote the upcoming pro package. Users are allowed to pay what they want before the launch to get the pro package then. This accounts for 2/3 of my revenue.

Now the question is: How do I make 1000$ in the next 28 days?