I've created an VB.NET application which I can implement in USA with the aid of an Sales Agent.

The tricky part is that the software itself will be free ... I will implement it for free to a BIG CUSTOMER. The real customers which will pay money are clients of BIG CUSTOMER.

So me and the BIG CUSTOMER will make money based on the subscription of those clients.

My problem is what payment schema should I implement so everybody will be happy. And also what kind of contract should I make and with whom

THank you