Sure, that sounds plausible. I'm not saying you need an enormous amount of money, but for this scenario you need supplies, car payments, gas, probably some kind of licensing fee, insurance, some kind of advertising, and a few months of rent and living expenses until you start making a profit. Maybe like $10,000, plus more as a safety net in case it doesn't work out and you need to find a job?
Even if they are lucky enough to have no debt, I don't think the average graduate has $10,000+ in the bank to spend. I have never started a business so I honestly have no idea how hard it is to get a small business loan for something like this, maybe it's easy, but even so it's certainly risky.