I say build your own. All you need is a piece of well piping and a smaller pipe to feed the air and propane, some copper pipe for the propane line, a small fan (hair dryer) and some firebricks and kaowool, inswool, etc. This is how they do it where I've taken all my blacksmith lessons and he forge welds from it too. Mine is built on the same design, and I think I paid less than $50 for the whole thing. The biggest expense being the kaowool and firebricks.