On Wed, Mar 8, 2023 at 11:55 AM Theodore Ts'o <tytso@mit.edu> wrote:

A year later, they came out with a version with X Windows, which made
it roughly comprable to a low-end Sun Workstation, at a price of $9k.
Given that in addition to the 3M's (1 MIPS, 1 Meg of Memory, and 1
Megapixel graphics display), it also adhered to the "4th M", costing
roughly $10k, or a "Megapenny". :-)

CMU's SPICE proposal was for a 3M machine at under $5K by 1985. But you are right $10-15K was typical in those days.