It's on sale for 2 days, and the first time I have seen this game for sale. It doesn't appeal to me as a Baroque music listener, but I am in a minority.
"Brütal Legend is an action-adventure that marries visceral action combat with open-world freedom. Set in a universe somewhere between Lord of the Rings and Spinal Tap, it’s a fresh take on the action/driving genre, which in this case is full of imitation cover bands, demons intent on enslaving humanity and Heavy metal tunes. Featuring the talents of comedian, actor and musician, Jack Black as super roadie Eddie Riggs, as well as cameos by some of the biggest names in metal music it's a wild ride in the belly of the beast that is not to be missed by gamers and Metalheads alike. "
it was part of a humble bundle a while back, but IIRC the minimum price that time was 10 USD.
I do believe this is the cheapest ever.
However Brutal Legend is now also avialable on GOG, so the DRM-free inclined out there may want to wait for GOG to have a sale instead. Either way, hurray for Tim Schafer