[orev]

> they marked up the price of roses ahead of Valentine's Day!

Simple supply/demand.

[dheera]

Has nothing to do with supply curve, it's just that roses on Valentine's Day change from elastic demand to inelastic demand.

In simple terms on Valentine's Day they can charge whatever the hell they want and people still want to buy it.

At other times of the year people have lots of alternatives to roses and are more price sensitive.