If anyone is looking for a cheaper alternative that is still a great boar bristle brush, I've been using this brush for about a year now.
(https://www.amazon.com/gp/product/B07YXBM4SZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1).
I was looking into a Mason Pearson for a while, but a friend told me that this brush was as close to a Mason Pearson that they had found while being a fraction of the price. I decided to try it and it's amazing. It has nylon bristles, which I didn't like at first, but they really help the boar bristles get all the way down to the scalp, which was something I struggled with, with other boar bristle brushes.
It's 35$ for the medium sized one I got, but comes in other sizes. Obviously there will be a difference given the price difference, but it is a solid wood brush, seems to be made extremely well, and it's super easy to clean unlike some of the other ones I have tried.