You could always forgo the $600 kit and just build it all by hand from pig iron and a nice piece of timber. 

I assume you're joking, but if not-

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I believe I might be able to help you there.
you'll need fire-clay, fast set Portland cement (it has more alumina, ergo its more heat resistant.), expanded Perlite, and playground type sand, a sturdy welded plate steel box, chicken wire, a length of 3 inch pipe, gaffers tape, and (here's where you get in trouble with the wife) a variable speed hairdryer.
you can get everything except the hair-dryer and the fire clay at Lowes, Home depo or the locally owned hardware store (<best option.)
Mixing instructions for the refractory here:backyard metal casting, refractorys
you can reach me at roper1911@gmail.com if you want more in-depth instructions.

or you could just dig a large Dakota fire pit and jam the hairdryer into the air intake, that works too... but only for small items like hooks, rivets, nails, neck knives, slip joint/friction lock knife blades, light annealing (cooling the steel very, very slowly. there by converting all ferrite to Austenite) and normalizing

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SPOILER WITHIN A SPOILER- spoilerception.... Ok now that I've go that out of my system, normalizing is the act of heating a steel to cherry, (about 1500 F) and letting cool to room temp. from what I've been told if you get it to much hotter you have to start over. which kinda sucks. as a note- check your metals alloy, high chromium and tungsten steels don't suffer from grain expansion like normal steel, so you don't have to normalize them.

(remember- normalize any forged working item- such as knives, hammers, tools and any thing that will bear a heavy load, be subjected to shock impacts(aside from nails) or have torque applied to it -at least 3 times to refine grain structure, I've lost more projects from bad grain structure then anything else- remember the Kukiri I made a while back?- Bad heat control = bad grain size + micro fractures.)

Warning- clock building instructions contained in spoiler.

Austenite is very workable. Quench it, and you get martensite mixed in - ridiculously hard, and so brittle as to be useless. Tempering refines out the martensite and hopefully leaves you with just perlite (the grains are made up of laminated layers of ferrite and carbon). Perlite is the strongest overall grain structure you can find in steel.