Free shows are a gift in themselves – as much money as the holidays cost most of us, a good show with musicians you’ve actually heard of put on at no cost to you in like a musical bow on top of a big fat present. WRMF’s No Snow Ball features Sara Bareilles, who you may have met when she explained that she wasn’t gonna write you a “Love Song,” and the electric Michael Franti and Spearhead, who you may have met at their energy-charged SunFest show in 2009.