Cracker,
I have been researching bison hunting for several years. There are a few outfitters that offer true fair chase hunts.
True fair chase hunts are in Utah and Alaska and cost from $5,000-15,000 with no guarantees. There are some great places to hunt buffalo that are ranging on huge pastures in several places. Those will all be contained in some manner.
Custer State Park in South Dakota claim to have free ranging bison (the B&C club even accepts this) but even those bison are 100% contained by a high fence. The B&C club overlooks it for the buffalo coming from in the park but they don't overlook it for the elk/whitetail/mule deer/antelope...a little hypoctricle but reality.
The biggest complaint I have heard from outfitters is that the client calls up requesting "I want it to be challenging, just not challenging enough that there is any chance that I won't get one" That is hard for the outfitter to thread the needle.
Unless you want to fork out thousands of dollars and run the risk of not getting one, you need to focus on some of the reputable bison ranches. Many of the good bison ranches where they are roaming on thousands of acres occur in North and South Dakota on the Bison River. You might try googling "Bison River". I have talked to several and there is one guy that kind of stands out.
There are also several guys in Alaska that offer the real fair chase hunts around Farewell.