On each item's page you'll see two prices listed: the rental price and the replacement value.

The rental price refers to the total cost of renting an item for the standard three week period. This price is calculated based on the cost of cleaning and freshening each item after wear (eg, dry-clean only garments will cost more than something that can be washed by machine). The rental price includes minor alterations and changes. 

The replacement value refers to the cost of replacing an item in the event of irreparable damage or loss. This amount will be charged if an item you borrow is damaged beyond repair, or if you fail to return an item. The replacement value is calculated based on the cost of creating a replica of the original from scratch, not the cost of buying more vintage stock.