For two hours' worth of the (now) funniest show on TV*, with several commentaries and a crapload of deleted scenes, I think $13 or so is a pretty fair value. Circuit ran a similar sale on it just before Christmas, and I was all over it. And after seeing how good Season 2 has been, I'm prepared to pay pretty much anything they want for that DVD set when it comes out.
I totally agree with you there. With Arrested Development's passing, The Office is now the funniest show on TV ... though I think that Scrubs can give it a run for its money.