Thrift store pricing is pretty good IMO. At least real thrift stores - those more curated vintage stores are, obviously, going to be higher priced.
But if you know how to check for quality materials and craftsmanship you can find really, really good clothes and furniture for unbelievably cheap.
The thing about fast fashion is, well, the clothes suck. They're more plastic than fabric, they fall apart, they look awful, they're not breathable, and on. You don't actually want to thrift those, because their lifespan is approximately 5 washes. Yes, it's that bad with some brands.
But if you can find nice cotton trousers or a great trench coat for 8-10 bucks you're golden. Just have them dry cleaned, press them, and you're going to be getting a piece of clothing that's higher quality than anything you can find in stores.
I found a great 3 piece brown tweed suit a bit ago. Miraculous all three pieces are there, dated somewhere in the 1970s. The construction was sturdy, the material was thick and rough, but everything was lined with viscose. The buttons were actually wooden, shaped like little hot buns. Multiple sets of them too, large ones for the pants and suit jacket and little tiny ones for the waistcoat. A suit like that made today would be at least 800 dollars. I got it for less than 50.
Point is, old stuff isn't low quality. Over the past 50 years, clothes have progressively gotten poorer in just about every metric. Yes, buying new cheap junk is sometimes cheaper than old stuff. That's because the new stuff is just so incredibly bad.
The stuff you're buying on Temu, Shein, H&M, whatever - is not competing with quality garments from decades past. They're not just not in the same category, there's many categories between them.