It is a lot of fun to visit Ancient Culture Street in Tianjin. I have been there on several occasions over the last five years. Like most things in China you have to take the good with the bad.
There are several shops and outdoor vendors with similar goods; most of which are worthless unless you are just buying a souvenir. If you are a serious flea marketeer, however, there are a few good purchases to be found in paper collectibles, such as rare Chinese comics featuring Disney characters (pirated, of course) from the 1970s. These are available from 3-10 RMB apiece (45 cents - $1.50). In the US, these comics are generally sold for ten times the high price at $15-20 at flea markets. I have purchased quite a few of them myself.
Buying jade here is a very tricky proposition; but if you must buy, buy something that is clearly an antique and not new and shiny. You can always get it cleaned later by a professional. Real jade cannot be scratched or cut with a knife. There is also a dull sound if you click it against another piece of jade. High-pitched clicks mean that the piece is artificial. Also look for two-tone pieces instead of one color; they are more difficult to reproduce. You should be able to pick up a very nice piece for the equivalent of fifty dollars (300 RMB), Be sure to bargain for everything you buy and do not show any particular interest in any item; just ask for prices to the left and right before choosing the item you really want to know about. Most of all, have fun and don't buy the first thing you see.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.