Sometimes you buy more than one thing at a time. The heuristic might be something along the lines of, if that store is 33% cheaper on that calculator it might be 33% cheaper on other things, and you might end up saving a lot more than $5. If the calculator is only 4% cheaper, your savings will only work out to near $5, which might not be worth your 20 minutes.
Sometimes you buy more than one thing at a time. The heuristic might be something along the lines of, if that store is 33% cheaper on that calculator it might be 33% cheaper on other things, and you might end up saving a lot more than $5. If the calculator is only 4% cheaper, your savings will only work out to near $5, which might not be worth your 20 minutes.