Once you have a butane/propane canister, you can refill it using an adapter and a butane can made for those cheap portable stoves. My local Asian store chain sells four cans of butane (227g) for $5. The adapter can be had as low as $1 on ebay. If you do this, please make certain the butane/propane canister is completely empty the first time. Propane is a much higher pressure than butane, and I'd hate the thought of the butane canister exploding in my hand. I know the butane cans have over-pressure relief, but I won't rely on that. Having stated the above, note that butane is not a cold weather choice. Pressure of butane is low to begin with and is only .8 psi at 32 degrees. Butane pressure drops off quickly after that. I use the butane in the canister when using a stove occasionally and for an Xcursion lantern in warm/hot weather. Basically, I use the butane for playing when at home, but for real use, prefer naphtha (Coleman or Crown fuel). Here's a pic of the adapter:
