Ah, this has been my latest ADHD fixation in my life since hunting season ended. So far, I've added Tractor Supply horse stall mats for flooring, a cheap squat rack, a bench, two olympic barbells, a curl bar, about 600lbs of iron plates, dumbbells from 35-80lbs, some resistance bands, jumpropes, and a plyo box in the corner of my pole barn.
I got lucky on the barbells, dumbbells and plates because my father in law had them in his shop for about 15 years collecting dust and decided he wanted them out. I have been shopping around for other options (I'd like to add some bumper plates, kettlebells, and more dumbbells), and I found what you are seeing. There are plenty for sale, but everyone wants nearly full blown retail for them. I've also noticed in my area that a lot of the local sellers from Marketplace/ Craigslist have bought up a ton of equipment and have a constant stream of listings around retail prices.
Also, I agree with the others above. Home gym is convenient, but I have to work hard to be consistent. I'm in mine 4 days a week at 5am, because if I don't make myself go, I won't work out at all. Secondary benefit in building out the home gym has been that your family can enjoy it as well. My wife has started adding in weight training with me a couple of mornings a week where she has always been into the HIIT workout videos and not seen much progress, and lately my 6 year old daughter has wanted to get out and do some workouts with the resistance bands and some of the lighter weights.