I think there is an oversized focus on everything being free. It started with Google being free but it really isn't since you have to view adds and get distracted.
Also think about a software tool that costs say $100. It ain't free but that's your hourly salary Mr. Professional Developer. Using only free tools is penny-wise and pound foolish.
Agreed; don't pick the free-as-in-beer tool solely because of that. However, some of the free-as-in-beer tools are the best. And those you should donate to (if they accept it). :)