The current pricing is partly an experiment to see if people will pay, and it turns out that 1 in 30 of those who sign up do at the moment. It's also to ensure that if the site explodes in popularity I won't lose money through Google Translate API costs. I plan to increase the price at some point (but not for current subscribers) although not sure what it should be exactly. What would you think of $4/month or $30/year options?
I'll think about increasing the 20/day phrase limit, I really need to dig into my analytics a bit more to see what the usage patterns are on this. Roughly how long did it take you to reach the limit and how much longer would you have liked?
Thanks again!