Nifty Amazon trick: I have a few DVDs from the Amazon black friday deals still waiting to ship (How I Met Your Mother S1: $12.99 & Flight of the Conchords S1: $14.99).
Since it hasn't shipped yet, I called up Amazon's customer service (a well-hidden number: 1-866-216-1072) and asked to have Serenity added to my order, getting super-saver shipping without having to find fillers. I did this last week with Katamari as well.
It says on the website to place a separate order, then choose "combine orders" after the fact, but it also states that you can't combine orders that have super-saver shipping. If you call them up instead of doing it online, you can bypass that little rule.
Anyone doing the Best Buy route: Robocop Steelbook 2-disc, Lost Boys 2-Disc and Dark Crystal 2-disc are also on sale for $8.99 this week...