Our chaotic Big Mac pricing test

Jutharat Pinyodoonyachet for BI

The price is the price. At least it's supposed to be.

We make exceptions — the cost of things like flights, hotel rooms, or concert tickets may move around based on supply and demand. Try to get on to a nearly full plane the day before it takes off, and you may pay much more than the person across the aisle who booked months ago. We may not always love the setup, but in limited instances, variable prices can make sense.

For most stuff, though,...