The hub from Ford is $200 new, if you can get the good price. Ebay has a few off brands new for a little over $100. I will be doing my right side+ axle soon also.
That center hub nut should be very very tight. The toque specs are over 150 lbs.ft. Basically tighten it as much as you can. Most people cannot break it. I have a friend who can. We bent a few breaker bars including helper poles, trying to remove a Taurus SHO crank bolt. We ended up using a torch to heat and loosen it.
Don't pull the axle out when the nut is loose, try to keep it in all the way, and almost level. The CV joint can be damaged if the axle is bent too much at the joint. Good luck,