What is the approximate monthly salary of a photographer in a studio?

That depends on the economic gap between different places. For example, in Shanghai and Shenzhen, the monthly salary of an ordinary photographer is 3000 ~ 5000 (excluding commission), while in some ordinary places it is 1500 ~ 3500 (most branches have commission). It also depends on the business and scale of that studio. This two people may not be very clear, so you should write down your city, which will be very punctual.