I don't think it makes sense to limit the number of applications, event types, or team members. Cost to your customers should scale with volume of API requests.
Volume is what costs you more hosting dollars. It's also a primary indicator of your customer's need for your service, and his ability to pay for it.
Restricting access to your other features only makes your service less useful on the low end, which is where you're supposed to be winning customers. It also sets up perverse incentives that leads to e.g. piggy backing multiple real-world applications into a single app on your site, having users share accounts, etc.
You should be looking align your incentives so that you succeed when your customer succeeds. Charging for volume does that.
Volume is what costs you more hosting dollars. It's also a primary indicator of your customer's need for your service, and his ability to pay for it.
Restricting access to your other features only makes your service less useful on the low end, which is where you're supposed to be winning customers. It also sets up perverse incentives that leads to e.g. piggy backing multiple real-world applications into a single app on your site, having users share accounts, etc.
You should be looking align your incentives so that you succeed when your customer succeeds. Charging for volume does that.