joker97: I might just get a $20 30cm bbq pan and do a very small fire ... :)
I built a deck and sunk a fire pit into it. The pit is about 1m deep, made from heavy bricks and mortor and the fire burns in a copper brazier in the pit. About a year ago, I realised the heat was going straight up and the fire was starving, so I half filled the pit to raise the profile of the brazier. The brazier is free standing, made from the old water heater and produces a healthy green copper glow. The pit is about 1.2m diameter and the brazier less than half of that. In the five years it's been there, only the occaisional coal has made it to the deck and then only to simmer out, having said that, there have been some big fires there and some long alcohol fueled nights.
The pit is half filled with rubble, is cleared out after every fire and the deck is the usual 10yo treated stuff, that I have found doesn't burn well at all even if you try. No accidents so far, always have a bucket and hose on hand and only sensible sized fuel goes in the fire. When not in use, the firepit has a matching cover that sits flush with the deck and can hold weight of people (the brazier is removed to the garden to be hosed down and cleaned frequently).
You'de be good with a pan and a brazier on top, but I have a few mates that found them to rust as they gather water or get left outside. The best pan I've ever seen has been a zinc shower floor from a scrap dealer. They are large (about 1sqm), have high sides (about 120mm to catch stray coals) and a drain hole (the old shower drain) plus they are good for outdoor/all weather use. Put bricks under each corner and you'll have a zinger of a fire pan. It'll warp if the fire is in it, so you still need a brazier, the pan is just to catch the stray coals and save your lawn/slab/deck.
Whatever you do, be sensible, keep it away from your house, keep it sturdy and level and check with council AND insurance clauses re: fires.
Good luck and post some pics if you build something yourself.