To raise yet another interesting requirements and design problem: How do we handle the case of multiple, conflicting pricing policies? For example, suppose a store has the following policies in effect today (Monday):
20% senior discount policy
preferred customer discount of 15% off sales over $400
on Monday, there is $50 off purchases over $500
buy 1 case of Darjeeling tea, get 15% discount off of everything
Suppose a senior who is also a preferred customer buys 1 case of Darjeeling tea, and $600 of veggieburgers (clearly an enthusiastic vegetarian who loves chai). What pricing policy should be applied?
To clarify: There are now pricing strategies that attach to the sale by virtue of three factors: ...