Kevin C. Cox/Getty ImagesPerformers don't get paid for appearing in the Super Bowl halftime show, but they usually benefit from increased sales and streaming in the days afterward. Billboard reports that all the stars of Sunday's show -- Dr. Dre, Eminem, Snoop Dogg, Kendrick Lamar, Mary J. Blige, special guest 50 Cent and even the late 2Pac, who obviously wasn't there -- experienced big sales bumps after the game. Billboard reports that according to MRC Data, sales of the songs heard during the performance increased by an overall factor of 775% compared to the two days prior to ...