Outdoor Tennis Center: 50 yuan/hour (night lighting fee is extra).

I have never been to the Peace Gymnasium! ~

Plastic yard of Tianjin University: 30 yuan/hour (our students hold student ID cards 10 yuan/hour).

General field of Tianjin University: 10 yuan/hour

Nankai University: 15 yuan/hour (it is said that it is not open to the public now ~)

Tianjin University of Finance and Economics: 8 yuan/hour (the venue is very rubbish, and it is far from the urban area)

Also, many residential facilities have tennis courts, but I don't know how to spend them. I suggest going straight in. If there is a security barrier, say it is a resident of this community! Hey hey! ~