Here is a goal: How do I know if the price at Costco is their lowest, or is it going to be cheaper later?

How would you accomplish this goal?

OPTIONS: a. If the price at Costco ends in .97 then it's their clearance price and it will never be lower.; b. If the price at Wal Mart ends in .97 then it's their clearance price and it will never be lower.;
a.