Hi, Hope you are doing well.

These are the Best government schools in India with low fees.
1. Kendriya Vidyalaya, Patton Thiruvananthpuram

Here the admission fees is just Rs. 20

2. Kendriya Vidyalaya, IIT Madras, Chennai
Here the admission fees is just Rs. 20

3. GVHSS for girls, Nadakkavu Kozhikode

4. Kendriya Vidyalaya, IIT Bombay, Powai

The admission fee is Rs. 25

5. Rajkiya Pratibha Vikas Vidyalaya, Dwarka, Delhi

For OBC the fees is 60 INR for 6 months, for general it’s 120 INR and if you belong to other classes then you have to pay a nominal fee.

(https://www.schoolmykids.com/schools/top-government-schools-in-india#1KendriyaVidyalayaPattomThiruvananthapuram)