Why does everyone always leave out one of the greatest ways to fund a company: customers?
Yes, I know, raising money helps you scale up to become huge ... but most startups never get to that stage. The easiest way not to run out of money is to make something that people want so much that they'll pay you for it.
A few years ago I went to a talk with a serial entrepreneur with one of the most impressive CV's I've ever seen. This guy has started more than 40 successful companies, the first one when he was seven, and had one of his companies sold for more than a billion dollars.
His formula for success is respect for customers. He said that he has never started a company without first having at least one customer. He also insists on taking engineers to sales meetings because they are great at selling technical products: They understand what they are talking about and they think what they're doing is really neat. Customers notice that.
Yes, I know, raising money helps you scale up to become huge ... but most startups never get to that stage. The easiest way not to run out of money is to make something that people want so much that they'll pay you for it.