Three prices at the rice aisle

A shopper in Manama stands in front of the rice and is paying three different prices at once, though only one of them is on the label.

The first is what she gives up by choosing. The large sack is cheaper by the kilo, but it takes the space in the trolley, and the money, that would have gone on lentils and a decent oil this week. Every yes in a trolley is several quiet nos.

The second is already paid. At home there is half a bag of an unusual grain she bought on a whim in the spring and has never enjoyed cooking. She keeps making it because throwing it out would mean admitting the money was wasted. But the money is gone either way. What is left in the cupboard is something her earlier self handed her, and she is allowed to decline it. Forcing it into dinners she does not like recovers nothing. It only costs more dinners.

The third is what one more adds. The refill pouch of pepper tips into the grinder she already owns, so buying it adds only the pepper. The new grinder adds a lid, a mechanism and another thing on the shelf, for the same pepper. When two options are otherwise equal, the one that adds less each time is usually the one she is glad of a month later.

None of this is complicated, and almost nobody shops this way. Most of us fold all three into one blurry number and feel vaguely annoyed at the till.

That is fine. Nobody calculates every trolley. But it is worth knowing which of the three prices is pulling at you, and choosing on purpose rather than by habit.