YY Beer House (粤园) claimed to be the most authentic Thai restaurant in town with its chef from Thailand. I went there couple of times & always enjoyed the Tom Yam Soup & Green Curry. Some of the food portion is small for the price but overall it is a good place for change of taste after too many Chinese or Western food. Average spending per person for a decent meal with 5 dishes should be around RMB60-80. They have a good selection of imported wine & beer too.
No. 3, Ao Men Road, Heping District (Behind International Buiding)
Tianjin YY Beer House