Question

When does the price of an item increase?

Answer 1

when it rises in popularity so they can raise the price and people will pay more for it (eg freddos /-/)

or sometimes the item price increases because it has cost the company more to make the product (eg shipping fares) so they need to charge more so they can still earn a profit (like fuel?)

Answer 2

When the Production of any good in a Particular year, is in decline, and if that good is very much essential for Human Being, then the Price of that Commodity increases.

Usually most of Natural good that is found on earth is very essential for Human being. So, when production of that good Decreases, then Price of that Commodity increases.