It's not hard to change it and yes it will need to be aligned.
Some of the aftermarket ones like the one I have have a grease fitting on them so you can grease it every oil change.
Umm.. I can't remember how much I paid for it. It wasn't too much though.
It seems pretty good.. like I said you can grease it so it won't run out and need "replacing" because there is no way to grease it. So I like that better.