I give free art on a personal basis to friends, or people within my community, or as an apology if I had to delay a project. The art I give for free is almost always just sketches, chibis, and cute, feel-good things. Without a paying commission, I do not and will not produce my highest quality, 12-16 hours work. Free work should only take a maximum of 2 hrs, though most only takes half an hour. Sometimes, as special holiday gifts for friends, I will put in around 4-6 hours. There is no way I will devalue myself or the illustration business to give away a week's worth of work. (I can't do the 12-16 hours in one go, that's several days of 4hrs at a time, so that I do not inflame my wrists, hands, or fingers with tendonitis, carpal tunnel, or arthritis).
I'm not going to say that a professional artist shouldn't ever give things away for free.
However, I do agree that you should NEVER work for free. There is a difference.
A gift is one thing, but if you feel you are doing WORK, then CHARGE MONEY.