So, I made a purchase the other day on equipment that is NOT neccessary for Calisthenics, but can improve your strength and allow you to do some exercises hard to replicate without.
https://www.amazon.com/gp/product/B016CHVAA8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
It is good quality and seems to be a good price considering all the other sites I checked. There is a way to make your own for about half the price. Using plumber pvc you get at lowes. I contemplated doing that, but in the end decided to go quality over saving some bucks. I don’t plan on stopping calisthenics any time soon.