Aren't Once and Avalleneda basically the same place, as in same name for the same place as Av. Avalleneda is the street that runs through the Once wholsaler commercial zone? It's in Floresta too, not Flores.
Either way, they are wholesalers who sell clothes to the clothing stores. These are not the clothing stores that are brands found in malls (Zara for example), but clothes suppliers for stores that operate as avenue retailers. As those stores can be hit and miss themsevles, so are the wholesalers. For every one on Avelleneda that has good clothes there will be a few with poor quality. In fact, even the good ones can sometimes lack the quality of a full brand chain. Regardless, some geuine bargains can be had and for the most part you are not required to buy a specific amount (I have never heard of this requirement in the many times I and family members have been). However, most of the stores will not allow you to try clothes on, so make sure you properly know your size if you head there.
Once is generally thought of as between Rivadavia and Corrientes, and between Callao and Pyurredon.
The "Avelleneda" district of cheap clothing is about 5 kilometers from there, in Floresta, as you say.
I would not call them the same place- they are quite a distance, and different in many ways.
Zara is an import store, not local.
Hardly comparable to locally produced stuff.
And I have certainly found Zara, H&M, and Target to be hit or miss as well, in quality and design.
Anyway, the rule in Argentina is always that varying qualities of products exist side by side, and you have to be an informed shopper- for anything, be it tomatoes, T shirts, or empanadas.
There are good quality Argentine made clothes- but you have to know what you are looking at, read labels, and observe how they are made.
As I mentioned above, I mostly buy 100 percent algondon clothing here, which is made from Argentine cotton- its quality, and a good value. But its still more expensive than Chinese or Bangladeshi synthetic clothing- which is also true in the USA or Europe- quality cotton or wool clothing costs more, and lasts longer.
80% of the clothes made every year, worldwide, end up in landfills or recycling within ONE YEAR.
mostly because they are designed quickly, made shoddily, and are made from plastic- literally.
Buy less, and buy better, and we all benefit.