I haven't made a buddy burner in a long time. In-fact the last time I made one I didn't even realize it had a proper name. The principle is extremely simple, it is a paraffin wax fueled burner with a large cardboard wick. I used to make mine in an old Kiwi Shoe Polish tin but any small metal can will do. I recently picked up a copy of "Roughing It Easy" by Dian Thomas, which jogged my memory about these great burners. She has excellent instructions for making your own.
Thomas suggests a tuna tin, her instructions are:
Thomas also constructs a stove from an upturned number-ten can; she places the burner inside it, punches smoke holes around the top edge and a door in the side to control the burner. The bottom of the can (now the upturned top) can then be used as a cooking surface. She also advises making a damper from the lid of the can attached to a coat hanger.
I made my stove as per her tuna tin instructions and used it with a Snow Peak titanium mug. The burner lit very easily and boiled 2 cups of water in about 15 minutes. I propped the mug on rocks and used aluminium foil as a wind shield. The burner worked well and it was cheap and easy to make. I have to admit it smelt odd and it sooted my cup to all hell, if I had the choice I would probably choose an alcohol or haxamine (ezbit) stove, but for a cheap, reliable alternative the buddy burner does fine.
If you come across "Roughing It Easy" pick it up. It's not too hard to come by and there is a lot of good stuff inside.