Markup

noun

1. The notation that is used to indicate the meaning of the elements in an electronic document, or to dictate how text should be displayed.
2. The percentage or amount by which a seller hikes up his buy-in price when determining his selling price.

   "You don’t make much money selling gas because the markup is so low."

3. An increase in price.

   "There will be a markup on those products next week; better buy them now."