Opportunity cost is a concept well understood, and often used in a theoretical sense, but not often is it translated into something easily understood.

In a store just before Christmas, I was tossing up between two brands of domestic coffee machine, that appeared pretty similar in all but price, the better known brand being substantially more expensive. The sales assistant sensing my indecision, and perhaps thinking I might do more ‘research” and he would lose a sale solved the dilemma by asking, “would you rather have” X” brand, or “Y” brand and 20kg of coffee beans?” 

That turned the theoretical “opportunity cost” although I had not considered it in these terms at the time, into something tangible that had a value relevant to the purchase, and made all the difference…… I took the “Y” brand machine and with the saving, bought some exotic coffee beans.