I think an oxy-acetylene torch is an essential early tool. With forging, heat is your #1 tool. With a torch you can heat small sections which is very handy (rivets, twists, sharp bends,etc.) Plus, you can weld. It isn't the easiest but if you get good with the torch welding with the other machines is pretty cake.
Get a drill press too. I make a lot of architectural crap and its rare I sell anything without a hole in it.