Also, if in one year you built a business that achieved that, you'd have to imagine it would continue to grow and make exponential amounts of money, so lets say year 2 you make $200K - why would you want to go to grad school then!?
Unless you've developed a minimum viable product and proven that people are willing to pay, if you really want to go to grad school, this would have to be the worst way about it. Get a normal job, a loan or whatever else. If it takes longer to get there then it takes longer.
There are several ways to fund your education in US, you can try to go to a universities where TA and RA positions are easier, these colleges are tougher to get into, but with good research they wont be that difficult. Also you are allowed to work 20hours on campus, you can try for CO OP jobs they pay around 10 -25 $ per hour, they may not cover your entire living costs but would cover substantial portion of it.
I saw your current twitter app, even though it is a nice implementation, professors and admission committees are looking for creative and research oriented endeavors, rather than skills for creating web apps. An MS student at a good company such as Google, MSFT, Amazon, Oracle, or Yahoo makes around 75 - 90 K a year in base salary and additional 25-30 k in stocks, options or bonuses. And then you would be much better equipped to launch your startup. a good PhD candidate earns even more. if you end up as a Quant on wall street you would earn significantly higher amounts.
Which universities did you get into? A good idea would be to work on a broader research subjects, which many professors in that university study. that will increase your chances for an RA position.
I am assuming you have completed your undergrad in CS or a related field. You should be able to grow faster if you give it a serious try. It can also allow you to add practical skills while getting paid and when you are waiting for your big idea to come up.
Good luck.
- What kind of apps your making - How big your target market is - How much you will be able to spend on marketing/sales
Because, on the surface, the goal of earning $40k is within reach, especially if you're targeting western markets.
My only suggestion would be to start making money ASAP. As soon as you have three months worth of actual revenue data then you'll be MUCH better prepared to make financial projections. They'll still be sketchy, but you at least need a baseline to work from. Every app and website is unique.
But, it's possible. It depends on your idea, execution, connections, etc. If you can establish some great partnerships, you will have a better chance at success. Good luck!
Search HN, there's other examples people have posted out there.
The question you want to be asking: Why do you want to go to grad school? Why not save money while working for a year for it? Are you able to "gain traction" with professors yet? i.e. get them to vouch for you, and possibly help you get into a TA program to help cover costs?
My opinion: given the time constraints you've defined, no, and you'd be better off working a job and contracting on the side.
Loan is an option, one can get loan for around 40k$ but it requires some property to be mortgaged.
Note: I am assuming a Good School [GATECH, Columbia, Cornell, TAMU, UT Austin, NCSU] and a good student.
you can pay back entire loan in at most three years, even earlier if you end up at MSFT, or similar places. Parents generally pay a significant portion of the tuition using their savings.
Also undergraduate education is damn cheap in India, Tuition is around 2K - 8K$ for four years. Hence most of the students are debt free.