That 3 inch long 1/8 brass pipe nipple cost $1.75. This will make two Burner Bodies.
Around here the brass pipe caps are made from 9/16 hex brass. That makes it easy to index the piece when it come time to slot it. They each cost $1.50.
That's a small chunk of brass from my scrap box to make the orifice plugs. The inside diameter of the brass pipe is nominally 9/32. That's not a common size for brass rod so I usually turn a piece scrap. I suggest that you anneal the brass before you turn it to size. I've broken the #71 drill going through hard brass. If you can get some 9/32 brass, it's one less thing to do. It will make a tight press since the end of the nipple gets compressed when it's threaded. We could be generous and say it cost 25 cents.
Let's see, that's a total of 5 bucks in materials cost for 2 burners. They are not real budget busters.