You got to be kidding! You need to give some specs - e.g. whether for a P & S camera (less than 1 kg) or for a medium format camera with very long lens (more than 8 kg) so that you can get some meaningful advice! Tripod heads are manufactured for different requirements and unless we know what these are, how can anyone advise you?
Your description is too general. There are many type of tripod heads available, each for different application. Do you need fast movement? Do you need precise adjustments? Do you need the head to assist you in alignment works?
Don't think you can get a Gitzo head for $150, even a used one.