Is buying boxing or MMA pay-per-views haram and is watching it haram?

It’s not haram as long as the guidelines of modesty are observed. For example, if a woman is watching and the men are dressed inappropriately while fighting or go into inappropriate body positions, then they cannot see such fights. .Otherwise it’s fine.

Inappropriately dressed means any dress that draws negative attention to his body, or makes a female gaze at his body such that she’s looking at its details