You can buy the cheaper ones at around $35. But you wont be satified with them. Short lengths and they will have alot of shake in them. Stepping up to a better camera arm will cost you quite a bit more. The Muddy tree arm cost around $200, but then you need a good fluid head to make the panning nice and smooth. Theres another $120 for that. Passthru on Kiskys website builds for lots of people. Including me. I just recieved mine and it looks super strong. Haven't got to use it yet, but i'm sure it will work great. He charges $165 for his and another $120 for the fluid head.
I guess it all depends on what kind of quality you want and the money you have to spend.