They want $5.44 for 2 cylinders. The small refill kit which has 1 cylider and 3 pads is almost $7.

The ones on ebay that Seth found require an adapter in order to work in a curling iron so I bet they won't work in a thermacell. The ones at wally world are made by thermacell and they're the exact same ones that come in the refill kits.