I've got 90.3% in boards and 79% in JEE. What all colleges can I get with a low fee?

You should go for TNEA and JAC admissions they provide admissions on basis of board marks. You should also try for Amity university, Noida it is very good in private colleges and they give scholarships on basis of board marks. I suggest you to call them and take guidelines from them, I can provide y

You can check the list of colleges you can get based on your rank here- https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor The less fee is applicable under Fee wavier scheme where you need to select fee wavier branch through Counseling. If your rank falls under Fee wavier category