If you use 1 pound propane tanks you know that they are expensive. Here is how you can fill them yourself

You need an adapter in order to refill the thanks. You can make your own if you are handy or just buy one like I did. Harbor Freight sells an adapter but you can get it for less from Amazon here : Gascru Brass Propane One Pound Tank Refill Adapter EZ Coupler P432

Here are the instructions :

you need a 20 pound propane tank (the kind you use for your grill), the adapter I mentioned above and an empty 1 pound propane tank.

Take the 1 pound tank and put it in the freezer. 15 minutes will do but I usually leave them in a couple of hours. Once you have cooled the 1 pound tank install the adapter onto the 20 pound tank and then install the 1 pound tank onto the adapter.

Then you invert the 20 pound tank and open the valve. You will hear the tank filling. Once you stop hearing anything turn the valve off, invert the tank and disassemble the tanks and the adapter. 

Thats all there is to it.