Oracle has an interesting Approach for licensing this which make sense.
You pay for your license based on how many CPU's/ CPU power of the server.

I don't know the exact rate but...

What it means in the end is you are paying for the "exact number" of users your internet server
can handle.

The other approach is a distributors license for the database engine.

Which has two themes.

Theme 1) We sell them a normal oracle license based on number of users and we get a small commission.
They can do whatever they want with the server within license guidlines and

Theme 2) We sell a RunTime license which is cheap for the customer and we get a larger commission.
But we are responsible for support (i.e. all oracle support calls go through us first) and the client can only use the server for our application . Nothing else.
But this is obviously useful for selling our App /w server ect.

You should just contact a rep in your area.

HTH