Don't buy a raspberry pi just for this, chances are you have some old windows machine you can slap Ubuntu server on and set it up easily. That's what I did and I have very little Linux experience.

My favorite thing about it is ad-blocking in mobile apps. I tried to use it with OpenVPN on my android phone for ad-blocking when I'm on cellular data, but the speed it was unbearable. I'm not sure if it was my crappy router or what, everything I read says that DNS routing should be neglibible to speed.

The downside of pi-hole as opposed to a broswer extension is it's more difficult to allow things when needed, and whitelisting specific URLs can be difficult and slow to take effect.