Another used tripod to look for is a big wooden Paul Ries. I don't know when mine was made, but the 6-inch-square platform says Made in Los Angeles, so I imagine it was more than a few years ago. The controls are big and strong and easy to adjust. It holds my Agfa 8x10 (heavy) rock steady. I paid $100 Cdn. for it at a used camera store.
Of course if you see a Ries for $100, jump on it, but that's quite a rare find. They are excellent tripods, but also very much in demand, and even quite old ones aren't cheap.