Everyone trying to get fit or who's goal is to get better at CrossFit needs a pull up bar at their disposal at all times, PERIOD. How many times a week do pull ups show up on a WOD? Sometimes never, sometimes too much. How much time do you have before or after class to practice kip or muscle up? Why not just throw one up in your garage, backyard, or even kitchen, whatever works for you. I am going to show you my personal garage set-up. It doesn't cost that much money, pretty easy to install, and when you find a support beam it shouldn't need any maintenance.
Tip #2: Figure out what width bar you like 3/4" or 1" are the standard.
Tip #3: Pick a height that is functional but not too hard to jump up and grab the bar.
Tip #4: Dont wrap the bar with tape or any rubber cushion.