Price lists are used if you have a different groups of customers that get different pricing.
For example, you might have a Standard Price List with a multiplier of 1 for regular prices and a New Customer Price List with a multiplier of 0.9 for a 10% discount. You can set the price list for each customer at the individual account level and you can also change the price list for an account for individual proposals.
Creating New Price List
Creating a new price list is easy. You simply select the product attribute that you want to use for grouping and select a multiplier. So, if you wanted to created a wholesale price list that was 75% of your standard price, you would do this:
You can also select other attributes like certain product categories get a different multiplier or certain product tags. You can have multiple rules for each price list and they are executed in order. You can even change suppliers be based on the price list an account uses.
NOTE: Changing a price list for an account or proposal requires EDIT permissions for Products.