In early 2007, I had the honor of participating in the Big 12 Business Plan Competition - a competition comprised of teams from different schools in the Big 12. My team placed third, and due to a fair bit of luck, all three winning teams were invited to the Moot Corp Business Plan Competition in Austin, TX. Each competition gave out cash prizes to top winners. I found out that another young entrepreneur there was financing his business by participating in (and winning) these types of competitions.
He had done the research to have a solid plan, and had a network that included a Senior Vice President at Microsoft (where he had interned). His idea was really unique, and was a benefit to everybody involved. His company was focused on a piece of software that was going to blow his industry away (and I'm sure it will). Since good programmers aren't really cheap, and he was going to follow through with his business anyway, he found thatĀ taking partĀ in business plan competitions was a good way to pay the bills. He financed a full time business by doing this, up to the point that he was invested in by one of the founders of Microsoft (after a meeting with Bill, of course).
If you want to finance your startup by winning different business plan competitions, follow his example by having a superb plan, the resources to get the job done, and the guts to do it even if you lose the competition. You may have to front the bill for taking a plane to a $100,000 competition, but hey - why not? It's doable!