The Price Books that you have created can be conditioned to the maximum number and minimum number of Products / Categories / Collections purchased where product price settings from the Price Book will be applied.
Minimum Quantity: The minimum amount of Products / Categories / Collections that must be met to apply the specified Price Book.
Maximum Quantity: The maximum number of Products / Categories / Collections that must be met to apply the specified Price Book.
Price Books Settings to Customers
The Price Book that you have created can also be conditioned for all customers, selected customers and selected customer groups.
In this column, you can set which customers / groups of customers are entitled to use the Price Book.