All bowls are not created equal
The quality of the bowl is important as it needs to both feel good in your hand and hold the shave soap securely.
This is a water based experience, so keep that in mind when searching for a bowl.
The point of the bowl is to hold the soap while you attack it with your shave brush. Building a lather with a bit of water using what ever brush motion works for you.
To do this you need to hold the bowl in one hand and the brush in the other. For this reason, you need to find a bowl that fits your hand comfortably and also holds the soap firmly.
Have a look through the listings on Amazon. There selection is huge and you can read reviews by past buyers.