Best Buy offers Firefly: The Complete Series on Blu-ray Disc for $12.99. (Amazon has it for the same price with free shipping for Prime members.) Opt for in-store pickup to avoid the $2.99 shipping fee. That's $2 under our mention from last month and the best price we've seen. (It's a current low by $8.) This 4-disc set includes a gag reel, all 14 episodes, three behind-the-scenes featurettes, four deleted scenes, and audio commentary for select episodes.