Yes, Microwaves were outragousely expensive back in the 70s. We bought a new Amana RadarRange with the "Touchmatic Controls" in Dec of 1978, right after X Mas,,it was 799.00 but did include 4 free lessons on how to use it, and several accessories such as a coffee pot, popcorn popper, griddle,,all for use in the new RadarRange.
Interestingly enough, that particular microwave DID last a good 30 years, without ever needing a repair. It did need a new lightbulb a few times, but that was all.
The control panel finally shot craps, but the actual microwave magnatron tube was still working, if you could get the control panel to get the magnatron to come on. I called an Amana store to see about maybe getting it replaced, and they laughed at me, saying there hadnt been replacement parts avalible for those models for many years now.
Finally trashed the whole thing, but it was the best microwave we ever had.