It's a pay as you go model. There's a small base fee, plus costs that scale as you use it. Originally, I had a 2 tier model, for basic and premium. But the feed

It's a pay as you go model. There's a small base fee, plus costs that scale as you use it. Originally, I had a 2 tier model, for basic and premium. But the feedback that I got from the beta users was that it wasn't granular enough. People who used it less wanted to pay less than the tiers could offer. So I switched to the pay as you go model.