So price started at $0.99 and a few weeks after the lunch on Product Hunt I was seeing around 1 paying customer per day.
Few weeks more and I'm seeing 2 and sometimes 3 paying customers per day.
So that's when I decided to raise the price, first I went from $0.99 to $1.49.
After that the sales keep growing, slowly but growing.
1 month later I raised the prices again to $1.99.
I was scare of raising the price too much and that no one will pay anymore.
But sales keep growing...
Waited another month and raised the price to $2.49, and each month I kept raising the prices a little bit up to $4.49.
Basically I kept raising as long as the sales kept growing or at least kept the same.