Rent cost is the daily cost (in coppers) to rent an item at an inn, as well as the daily cost to store that item.

When stored over a long period of time, the cost (in coppers) to retrieve a stored item is equal to the following:

$ Storage Cost = Days Rented\times \left \lfloor \frac{Rent cost}{4} \right \rfloor, \mbox{where } DaysRented \le 365 $
Note that $ \lfloor x\rfloor $ means the greatest integer less than or equal to $ x $.

Rent cost is independent of and not to be confused with item value.