I haven't worked with mainframes since the z10, but back then you could get into an entry model for about $100k.

Though the sky is the limit. The typical machine I would order had a list price of about 1 million. Of course no one pays list. Discounts can be pretty substantial depending on how much business you do with IBM or how bad they want to get your business.

It depends on how full those drawers are. $250k to $1m would be the typical price range.

It's easier and harder at the same time to buy older hardware. That's half the challenge though because the software is strictly licensed and you pay per MIPS.

Here's a kid who bought a mainframe and then brought it up:

https://www.youtube.com/watch?v=45X4VP8CGtk

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.

You can get a software emulator for free and run it on a PC! It's quite robust and used by IBM's own developers. https://en.wikipedia.org/wiki/Hercules_(emulator)

You don't buy a mainframe, it's consumption based pricing. They aren't just going to list a price, because they need to size the hardware to what they think the workload will be.

Could they just list prices? Sure. Will they ever do it? No.

It's probably impossible to say because of the service contracts that come with it. Nobody would buy one brand new and not pay for support and consulting too.

If you have to ask, you can't afford it!

A Rockhopper 4 Express starts at $135,000. While technically a mainframe, it won't run z/OS.

I think leasing is more common.