It was a million an episode. That's about what Star Trek: TNG cost, but TNG had the advantage of never not being in syndication. By way of comparison, Terra Nova cost about $4m an episode... and Game Of Thrones (Season 1) came in at around $900k/episode. BSG? About $1.4m per episode. Which isn't quite a fair comparison, because the economics of HBO are a little different. Nonetheless, Firefly was a network show, and it needed to make network numbers. NCIS costs around $2.5m per episode, but it also delivers 8 million viewers on a bad night. Firefly never got above 5. It would have had more of a shot on cable than it did on network. Problem being, Fox didn't run it on FX, while NBC chickened out and ran Battlestar on SyFy. There were some serious issues of mismanagement with it all. There often are with Fox (which is rapidly becoming The Gordon Ramsay Network). It would have been different on CBS or NBC, and would have been exactly the same on ABC. Kind of a shame. It's about the only Whedon thing I can stand.
It was stupid expensive and nobody watched it. Primarily because it sucked. "Oh, shit! We're about to be eaten by a dinosaur and we can't run! What will we do?" -COMMERCIAL- "Boy, we sure are lucky that dinosaur got bored and left while we were during commercial; let's waste some time on some super-thin bullshit human interest b-story, shall we?"