How much can vary a bunch. Basically $2000 - $6000 for most "normal" outfits ranging from a drop camp to fully guided. You can certainly spend a bunch more for premium tags & lodging.
Nothing against guided hunts, they can really increase your odds and make the planning and execution a lot simpler, but it really is a very doable hunt on your own. Works better with at least one buddy.
You might try and narrow down what type of hunt you are thinking of. Drop camp, fully guided horseback, lodge based, 1 on 1 or 2 on 1 guiding, spaghetti and a coke vs prime rib & wine.