I can only talk from the consumer point of view, as a long time resident in China. but still, it may give some idea of where things are. First of all, a recommendation if you want to learn a bit more about clothing manufacturing in China: this documentary.
China is already losing competitiveness in the worldwide clothing manufacturing. Producing in Thailand, Bangladesh or Vietnam is cheaper and even the big Chinese manufacturers are moving there (ask Li & Fung, for example).
Consumer prices in China are difficult. even sven, for example, talks about some consumer prices that are only true either for foreigners who don’t know how to get them lower or for well-to-do people in the main cities. The price you pay for clothes in China, as the price you pay for anything else, depends on who you are and how well you can negotiate. In that sense, it is a bit misleading to talk about “real price”.
In Shanghai, where I live, it is said there are three prices: the laowai (foreigner) price, the Mandarin-speaking chinese price and the Shanghainese-speaking Chinese price.
Quality and price are not independent. Usually when you pay little you don’t get as good quality as if you pay more, that is true everywhere. However, in here high (and I mean high) prices, in my experience, do not mean better quality.
Let’s go to the examples:
Shirts: A normal store can charge you around 60 yuan for a long-sleeve formal shirt. A high-end store can charge you perfectly a couple of hundred or more. A cheap place in a fake products market or a small store in a normal neighborhood can charge as few as 30 yuan, and having the shirt made for you in the tailors market can throw you back around a hundred, I think.
Shoes: Taking into account that is difficult to get sizes bigger than a 40, my wife just got a couple of pairs of heeled, high boots. Chinese brand, cow hide. Chinese taste. Around 400 yuan both pairs (59 USD). Having shoes made can mean around a thousand yuan, and a high end store can actually ask you to give them one of your eyes in return.
Baby clothes: It might not be the example you are looking for, but for me it is easy to talk about it now We have several high end stores in Shanghai, including, case in point, Mothercare. Prices in Mothercare are quite similar to what they are in Europe, so basically is a shop for expats and wealthy Chinese. As a second tier, you have the Chinese brands, more or less well known, from Goodbaby (Mothercare is in China through a JV with them) to Lijia or similar. As a third tier you have markets with small shops like Puan Lu…
Price for a long sleeve bodysuit:
First Tier: 50-60 yuan
Second tier: 30 yuan
Third tier: 10-15 yuan
The interesting thing is that the third tier clothes are also Mothercare branded, and a very similar quality to the ones you can buy in the real shop. Why? Well, there are two reasons: clothes that do not pass the quality checks because of things like mistakes on the colors or the drawings, and clothes that come from over manufacturing (the Mothercare suppliers keep the machines producing a bit more than needed and sell the surplus to the local market).
End result? You can find very good prices AND qualities, if you know where to look.