Thanks kd7fqd. I could have read Amazon's description of the stove I bought for the answer.
...Type of Fuel: Butane, 8oz, 227g * Gas Consumption: 160g/hour * Nominal heat input: * Heat output: 7,517 BTU's/hour * Min. Burn time: 1hour 40min./cartridge * " ...
I s'pose those numbers are for running it at full throttle so that's worst case. I usually back it off a bit so maybe two hours per can as a plan. $1.25 plus tax per can ($10.75 total for eight cans at a local Korean market) is cheap considering the convenience and performance.