Well TDA, I am envious of that, in fact, I have just finished my first 45kg bottle that was commissioned full when I fired up the new brewery and it did 24 brews before running out.
That works out at $2.83 per brew based on the, then purchase price of $68.00 for the 45kgs.
In the new year my brewery is getting 2 Nasa Burners, a Kirby temp control for my herms for mashing and a 90 litre kettle. It's frame is also getting cut down so that the HLT and the Tun are on the same level thus eliminating the ladder.
With these mods I will be able to do 50 litre brews for what I consider to be the same operating cost, not including the extra ingredients, as what it is costing me now to do 20 litres.
But having said all this, it still wont be as cheap as getting the gas for NOTHING.