Hello Dave,
Each Developer license includes one Server license by default. We are providing the following volume licensing discounts:

3 to 4 licenses - 10% discount
5 to 9 licenses - 20% discount
10 to 19 licenses - 30% discount
20 or more licenses - 40% discount

A server license will be required for each production report server license (running reporting services).

Best Regards,
Nevron Support Team

I see that the initial package includes one server license and one developer's license. What is the price for additional developer's licenses?

Also, can just one license be used for clustered servers?