"Selling enough records to make another record."
Rick Rubin started DefJam in his NYU dorm. Steve and I built TSR in Curtis Hall, and I went on to build my publishing business in my wife's dorm at NYU. It happens more than you might guess, and the reason it works is something you can use, even if you're not in college or living in a dorm...
You sell enough records to make another record.
You're not trying to sell the company or to make a huge payroll or to make sure the stock options are in place. You're building something.
The only way to build something when you don't have money to invest is to make something so great that people will pay for it in advance, that they'll eagerly sign up to use what you're making. Now not later. Now when it's new. When it's useful and fresh and interesting.
Too often, we look at the serious nature of starting a business (and worse, our imagined serious implications of failing when we do so) and we forget about useful, fresh or interesting. We forget to do that thing that might not work, to expose ourselves to things that are generous and new and fun.
You don't have to quit your day job to start something, just as you don't have to drop out of college to do so. You have weekends and evenings and all that time you're online...
Make another record.