So this morning I tried Williams Mug Shaving Soap, which I purchased for the grand total of $2 from my local grocery store. It came in the form of a white hockey puck and smelled like.....soap (meaning I could detect no added scents).
So....it's cheap.
I watched a YT video on this stuff before I purchased it, so I knew to soak it in hot water for five minutes before trying to lather it, which I did, along with soaking my new Omega boar hair brush in the same mug.
After that, it lathered well, with a bit of effort. I was able to do a three pass shave with my Merkur safety razor on a four day beard, which was my fourth shave with that same Wilkenson Sword blade, with no nicks or cuts. I then disposed of the blade in a sharps container, which will probably take the rest of my life to fill at the rate I am currently going.
As for the Williams soap....meh. The lather was mediocre, but functional. I prefer the lather the green tub Proraso produces, and the Proraso has a nicer fragrance.
But, the Williams soap is very inexpensive, so if that is your main concern, it should do quite well.
I'm new on this journey, so I plan to try many different soaps, blades, and brushes.