This is a bad time to build a home gym. All of the used equipment is priced double or triple or more compared to pre-shut down, and the gym suppliers are out of a lot of the most basic stuff.
that said, you can do a lot with a set of dumbbells that tops out at 50 lbs, a pullup bar, dip station and an olympic bar and bench.
I feel lucky because I have a really well equiped home gym (deadlift bar, squat rack, flat bench, incline-decline bench, dumbbells every 5 lbs to 110 lbs, dip station and pullup bar, plus bands and 700 lbs in olympic plates) and my coach is giving me some really great programming so I can train at home. So far I haven't lost any of my strength and seem to be making some slight progress.
On a side note: I sold some of my extra equipment to a friend, for what I paid for it. So he now has the ability to deadlift, squat and bench press. I could have sold it for quite a bit more on craigslist, but I decided I would rather sell it to a friend, than to price gouge.