Step 1 - build a product. make sure it has lots of bugs and is unstable.
Step 2 - roll out a premium product that's the same product, just stable, and less buggy.
Profit.
How is charging for an API not a finger to the developer community? Facebook for example doesn't charge for their API access. They charge for the products that the API has access to. If I have access to a product, I shouldn't need to be charged for the APIs to access that product