Well, I don't shop at most of the places mentioned in this thread or buy designer clothing. Do I win the internet now?
The reason has nothing to do with labor or quality or style or money or anything else. The simple fact is that once you get to be past about size 16, you just plain don't exist in the designer fashion and the vast majority of the fast fashion world. I don't shop in H&M or Zara or F21 because nothing in there fits me. I don't buy Burberry coats or
Prada dresses because they don't make them in my size. Period. I made a little excursion out to Rodeo Drive last spring, there's also NM, Saks and Barney's near there, and not one of the vendors in any of those stores or boutiques had a piece of clothing that I could wear.
Yes, I'm a little bitter.
That's not to say I would spend the money on them if they did, but I might consider it for the right piece and the right discount.
As for the original question in the OP, I actually started out the opposite way. I started upgrading my clothes from Target and Walmart and Mervyn's (back when it existed) to Macy's and more recently
Nordstrom. I also love Torrid and sometimes Lane Bryant. This came about by watching What Not To Wear and seeing that going up in price a little meant better fits and more tailored cuts, more attention to detail, less cookie-cutter fit-the-masses cuts. Sometimes better fabric too, but I have been disappointed in the amount of polyester that they still want $$$ for. I just bought a Ralph Lauren dress that's nothing but polyester.
And then I started moving up in bag from Target/Walmart to
Coach/MK/DB. Haven't made it up to LV or Balenciaga or any of that yet, we'll see. Still have a tough time justifying $1000 on a purse.
I think by far the biggest thing about looking good is proper fit. A $20 Target dress that fits well is always going to look better than an ill-fitting $1000 designer dress. You just can't look good in clothes that don't fit you well, and usually you don't feel very good in them either. After that it becomes about taste and styling and wear and all that, but it starts with the right size and the right shape for your body. And maybe a little help from a good tailor on occasion.