Do like Madcrow said, and make your own. After all it is a forge......
Also if you want to get ready made tongs, look for a Farrier, (Horse shoe maker) and see where he orders his supplies, or go on line, and look up either blacksmith supplies, or Farrier supplies, or check out some farm supply stores. As for using concrete, I would recommend using fire clay, that is used in making fireplaces, and bar B que grills. Get a variety of hammers, five pound sledge, large pall peen, and small ball peen, good heavy duty wire brush, welders hammer, Welders glove, and apron, and good eye protection. You can use a heat gun for your forced air, as it is hot and adds to forge. Keep your eye out for stuff for sale on the internet, and yard sales, and antique shops. A good heavy duty vice is a must have, and try to get an OLDER American made one, as the Chinese crap, is cast iron, and will bust apart when you use the little anvil on it. Also speaking of Anvil, a good one is a god send. The pieces of rail iron, are good for small projects, but a good sized anvil is a big help. 200lb, or more, if you can find one, but a hundred pound will suffice till you can get a bigger one. You want the top of the anvil to be at your middle joint of your fingers. Set the anvil on a good sturdy stump, or metal frame, or solid platform of 2x4's or 2x6', etc. nailed, or screwed together to form a base for the anvil. Just fold your fingers at the middle joint, and they should rest on the top of the anvil, and that will be your personal optimal working height. I read where one noted blacksmith, said he thought that steel worked over charcoal made better steel, than the gas forges. I don't know if this has to do with the charcoal imparting any carbon to the steel, while it is being heated, or not. He said it was just his opinion, having used both methods. Anyway, check out those sites, and good luck with the "Black" Art.
Wayne