Cloud guys appreciate the information you have provided. Unfortunately some concepts are very confusing and hard to grasp for me, should have taken MBA or something
You don't buy a mainframe, you're leasing it.
Theoretically you can still buy one, and probably even buy permanent licenses, it's just cheaper to lease - especially since leasing will often mean IBM will send a beefier mainframe that you can online "upgrade" by changing the sub-capacity licenses.
pricing is achieved via SAP, so you can imagine how even the people working there have no idea of the real price :)