Answer: There are 3 different roles you can select when setting up a new buyer. Here is what each permission allows the user to do.
Additional Buyer: If you give the user the 'Additional Buyer' permission, This will give the user all the same features as the default or main buyer.
Non Buyer: If you give the user the 'Non Buyer' permission they will be able to see prices across the site and view items, but wont be able to proceed to the checkout with an order.
No Prices & Non Buyer: If you give the user the 'No Prices & Non Buyer' permission, This will give the user very minimal control over what they are able to see and do on the site. If you give the user this permission they will be able to browse the site and add items to the basket but they wont be able to proceed to checkout with the order out and see any prices across the site.