Free: Contests & Raffles.
They also make a range different size canisters. I don't know if that's a statement of the obvious, but it would seem to moot the concern about never having enough for a trip.
i have been geeking on stoves for the last few years. a few things i have found.. i avg about 4g fuel per boil. i scratch my boils in the side of the canister. i have a bone empty cyl at home to tare the scale, and then grams of fuel in a partial, to take them on shorter trips. with the stoves like JB and reactor, you dont need to crank them. just enough for the flame to cover the fins. i am averaging around 27 boils per 110g fuel can, in the casades and rockies. the pots with fins do make a huge difference. dont boil in the wind, it wastes a ton of fuel. my sol ti pot finally died, after 200 or so boils.