Hey there, 

If you're looking for affordable colleges for BA in political science University of Delhi is the best option for you! 
I'm gonna list a few colleges for BA in Political science in Delhi University
1) Lady shri ram college for women
2) Gargi College
3) Hindu College
4) Hansraj College
5) Miranda House
6) Delhi College of Arts and Commerce
7) Shaheed Bhagat Singh College
8) Sri Venkateswara College
9) Jesus and Mary College
10) Daulat Ram College
However, In order to get in any of these you'll require a minimum of 94-95% best of four in 12th grade if you're from general category and almost every college affiliated with University of Delhi has under 20,000 per year fee structure. 

Hope this helps.