Even if you do hundreds of projects for free, if the result lacks quality, it will be likely useless. I guess the point of doing projects FOR FREE, as mentioned by most of them, is to have a work portfolio to show to your future clients and somehow to market yourself or your skill. People always like discounts and/or "free" stuff. But if you already got the knowledge and expertise and able to deliver quality projects, why still accept projects for free? You don't always have to apply what you read.