There are much cheaper Microsoft ergonomic keyboards, even if the 2 keyboard halves are not separate, so you cannot adjust the distance between them or the lateral tilting.
I had been using for many years Microsoft ergonomic keyboards and it was still much more comfortable than with a classic keyboard.
A few years ago I have switched to a really split keyboard (Kinesis Freestyle), which was an improvement over Microsoft, but not a so great improvement as Microsoft was over a standard keyboard.
Unfortunately, Microsoft has first discontinued their cheapest ergonomic keyboards, which had almost the same price as standard keyboards. Then the remaining more expensive models have been sold to Incase in 2024, so they can now be found "Incase Designed by Microsoft" products, but at significantly higher prices than when they were made by Microsoft. Even so, they might be the cheapest ergonomic keyboards of decent quality. Microsoft still sells a "Microsoft Surface Ergonomic Keyboard".
Old stock cheaper Microsoft ergonomic keyboards may still be found at certain shops.
On eBay and the like a lot of old and very cheap Microsoft ergonomic keyboards can be found, but buying a "pre-owned" keyboard is risky, as you do not know how worn out it is. Moreover the wireless MS keyboards used proprietary USB dongles paired with the keyboard. If an old wireless keyboard is sold without the dongle, it cannot be used unless it also has a wired connection.
For someone who types all day, there is a great difference in comfort and fatigue between a classic keyboard and a good ergonomic keyboard. Young people typically do not care much about the quality of their keyboards, pointing devices and monitors, but after decades of using computers every day many of them regret their negligence, which could have avoided unpleasant health problems.