It's going to be different from place to place.
I lived in NW Arkansas for a little while. It's an interesting place, because lots of young people move there for big (relative to the local cost of living) salaries, and then move away again in a few years. You can google whose headquarters is in Bentonville, AR.
Anyhow, that means they buy lots and lots of brand-new stuff. Furniture and housewares and clothes and vehicles. And then since those things are expensive and inconvenient to move to the coast, they leave them behind. The thrift shops in the area were so full of awesome, expensive, barely-used goodies that they wouldn't even stock it all. They'd just throw things away.
The dumpster behind the Goodwill, we called it the Golden Goose. You go peek in every once in a while, and there was always something magnificent.
Now we live in Michigan, and what's on the shelves in the Goodwills here is inferior to what was in the dumpster there. It's just different place-to-place.
In both places, I've had wonderful luck at recycling centers. The kind where they keep big bins, and you drop off your recyclables there? I hear the center gets paid $14/ton for glass, so the employees at all the different places were perfectly content to have me take away all the glass I wanted.
Cardboard was similar. Metals have much more value, but that's mainly aluminum and copper, not so much steel. So steel
coffee cans, I could always have as many of those as I wanted. I never asked for any aluminum.