Its actually really easy - there is a bolt at the bottom and the top of the shaft, to access the bottom bolt you have to move the plastic collar out of the way. It just snaps in place, you can pry it loose with a screwdriver.
Once you have the 2 bolts removed, pull off the shaft. Its collapsible so it can be a little harder to get back in. You have to tighten one end down, then line it up and stretch the damn thing back into position.
As for the price of a new one, I have no idea.