1) I think you'll lose conversions at signup when people are tasked with trying to figure out how many "API hits per hour" they'll need. What qualifies as an "API hit"? What happens if you go over your API hit allotment? Does your site just stop working for the rest of the hour?

2) What qualifies as a "user" on a site? If I am a web developer using the service, do myself and my client both qualify as individual "users"? Can we both use the same account?

To simplify the packages I would probably split them up into three different tiers:

Free - 5 Pages

Basic - $10/mo. - 20 Pages

Advanced - $20/mo. - 100 Pages

I would give all accounts unlimited users and unlimited "API Hits" to reduce confusion. If an individual account is bogging down the system I would deal with that if the time comes rather than try to explain to people what an API hit is.

One thing I find curious is that it appears that the client's server requests the data from BitsyBox via a PHP include in which case I am wondering about the content delivery via CDN claim. Wouldn't Amazon be delivering the data to the client's server, at which point the client's server would push the data out via whatever path it wanted, as opposed to the data being delivered directly to the client from CloudFront/S3?