I picked up a similar heater to this a few years ago on chuckout at BigW, and it gets a good workout during the cooler months. They run off 220g butane cans that can be bought in a 4 pack at many places for less than $5.
If you're going to run it flat out, Aldi says it will last a little over 2 hours on a single can. We tend to not have to run it flat out most of the time and tend to get about 6 hours from a can of gas. Great for camping and outdoors. NOT for use in enclosed spaces.
EDIT
Specially for JV ;) They're usually around the $100 to $150 mark
Butane's a bastard gas.