IIT

NITs and IITs provide fee waiver depending on your family annual income. Score best and you will receive various scholarships and you may apply for education loans also. After joining the NIT or IIT you will be able to see many types of scholarships based on your study and income.
Your options are
While joining in the college they'll ask about the income
of your parents. At that time of your income is less than 1 lakh per annum then you will be able to study in those institutes for free of cost for study only by submitting income certificate from respected issuing authority.
And there will be a lot of scholarships for economically backward students and don't miss to opt them.
And there will be a lot scholarships for clever students that is high GPA students and students who pass their tests and be wise to opt them also by working hard and getting good grades and make use of it .
And next thing is you can get loans from bank . You can go to the banks and talk to them about the education Loan and they will guide you how to avail it .
Hope this is helpful !!
Thank you !

In my opinion, CSE should be the best option as it covers various IT fields it will give a wonderful image of the numerous possibilities in IT fields. Now you have a lot of business ideas, by studying CSE your views get a wider angle or you will get some additional ideas. Remember that IT fields are inevitable for any entrepreneurship. Some of the additional pieces of advice that I want to give
1) Think about all the problems you may face, and then start. If you had started then don't give up until the success came across.
2) Make like-minded friends circle in the college and start teamwork, the set of different ideas would end up in innovative and progressive startups.
3) Stay motivated and work hard.