Hi, Can you advice me where i can purchase cheap things in Tianjin like in silk market in beijing?

Well, you can go to Ancient Culture Street (Gu Wenhua Jie).

There are many traditionally designed stores that located at the both sides of the street. Tourists can buy Chinese traditional paintings, calligraphy, jade and crafts. It is a good place to find souvenirs and enjoy the architectural spectacle.
Most products have reasonable price.

This street is located nearby the intersection of Tongbei Road and East Road. You can find it easily. Hope you like.