How could this old sign be worth $1200? I haven't a clue. But this website seems to indicate that Grizzly Gasonline used to be drilled and refined in Montana.
The Shelby Promoter, 1938 - The Northwest Refining Company from Cut Bank opened a new bulk plant in Shelby Montana, featuring Grizzly gasoline, which is widely accepted by motorists in northern Montana, and is made entirely from Montana crude oil.
Location of the new plant is south of the railroad tracks, directly across from the Sullivan Hotel. A. J. Wilcox is the distributor of the gasoline.
This company was sold to Carter Oil a subsidiary of Standard Oil Co. of New Jersey in 1944.
So who knows? Maybe the Saskatoon seller of this sign has an important and valuable piece of automotive history?
http://saskatchewan.kijiji.ca/c-cars-vehicles-other-Grizzly-Gas-Porcelain-Sign-W0QQAdIdZ253818876
