Okay, I admit I was wrong about the two months thing, But here's what Eric Wilhelm wrote:
We have not finalized the pricing, but it will be reasonable, and you will be able to join for periods of one month, one year, or two years. Initially, we'll only accept payment via PayPal. Every user who has registered prior to the release of pro accounts will receive at least 3 free months of access to the existing features we are turning pro. During this period, we hope to convince you that the features are useful enough to pay for.