Objective: How can you tell if a product you are shopping for at Target is at it's lowest price?

Which of the following solutions is more sound in terms of naive physics reasoning?

Choose from:
[I] Check the price. If the price ends in an 8, it will likely be marked down again soon. If it ends in a 4 it will never be marked any lower.;
[II] Check the expiration date. If the date ends in an 8, it will likely be marked down again soon. If it ends in a 4 it will never be marked any lower.;
[I]