I'm very much against integrating an integral service of a website without understanding the pricing structure of the service. I know it says Free, but until what limits, for how long .. ?
I can understand that - to be honest we're still trying to work all of that out. I'm going to try to write up some more details to address this concern. The short answer is it will be free as long as you are "small" although I need to define that and what happens after that. We definitely plan to have that in writing (for both parties benefit) before going ahead with anyone.