In many cases the expenses related to buying them mean the margins are tight.
Start by buying candles, oil lamps, a camping stove, barbecue, and a wood-burning rocket stove if money is tight. Anything above that can end in flourosis or poisoning. http://WWW.Xn--9I2Bz3Bx5FU3D8Q5A.com/bbs/board.php?bo_table=free&wr_id=837024