[bigbuppo]

The big problem is that everything in IBM-z world is negotiated, and often covered by NDAs. The pricing is complicated by which operating systems and what sort of workloads you'll be running, and what service level guarantees you need. The only published pricing in the entire life of the IBM 360/370/390/z-series line was the Linux One when it was first released... Hardware plus OS, excluding storage, was $70k on the low end.

Previous generation machines that came off-lease used to be listed on IBM's web site. You could have a fully-maxed-out previous-generation machine for under $250k. Fifteen years ago I was able to get ballpark pricing for a fully-maxed-out new machine, and it was "over a million, but less than two million, and closer to the low end". That being said, the machines are often leased.

If you go with z/vm or z/vse, the OS and softare is typically sold under terms that are pretty much like normal software, except it varies depending on the capacity level of the machine, which may be less than the physical number of CPUs in the machine, since that is a thing in IBM-land.

If you go for z/os, welcome to the world of metered billing. You're looking at tens of thousands of dollars in MRC just to get started, and if you're running the exact wrong mix of everything, you'll be spending millions just on software each month. There's a whole industry that revolves around managing these expenses. Still less complicated than The Cloud.