RE: Minimum optics for Western hunt.
If you don't need waterproof (which you should not on an Arizona hunt), you can get some very very high quality glass at a very reasonable price. Once you need nitrogen filled and waterproof down to 3 meters, you are gonna pay for it. Try eagleoptics.com. Give them a call. These dudes know their glass, and I bet they can hook you up with some fine binos for a good price.