Here's a neat article from Rolling Stone 9/20/79 for buying stereos based on entry to professional level. Multiple the price by 3 or 4 and you'd have today's pricing. Even the entry level is somewhat pricey, I know when I was a kid I never saw much more than mid-level systems. I think 1978 is considered the golden year for mass-manufacturers, 1979 was different, it was a year manufacturers were seeing a sharp decline in sales but on the upside, boomboxes and personal cassette players were seeing the first real interest. https://www.rollingstone.com/music/features/the-incredible-stereo-hunt-19790920
Don't forget to read the sidebar article on PC's vs Home Stereos from 2001. https://www.rollingstone.com/music/news/the-digital-beat-pcs-vs-stereos-20010508