Surprisingly the cost of products from well established stores are roughly the same as in the US. Li-Ning seems to be one of the most popular sports brands here (probably comparable to adiddas and nike in the US). The strangest thing I found was that although Nike and Adiddas (also apple) products are made in China, they are still the same price or more in China. I'm pretty sure this has something to do with the American brand name and logo pasted onto the products. Fascinating how supply and demand works. By creating a demand for American "quality" products, you can jack up the prices of products you created in your own country. Examples would be Li-Ning vs Nike shoes. Li-Ning prices are more or less reasonable while Nike is just way out the roof.
Along with the fantastic shopping and wandering around, culturally, I didn't see too much of a difference in outdoor shopping from say California to Tianjin until we got to the outdoor eating place. It was pretty awesome to be able to eat thing off a stick and chill around. The only thing remotely close to that market is the state fair in Minnesota which only happens once a year.