Amazon has quietly introduced a new service connected with the lockers it has been installing in city centers for some time now. Located in various garages, corner stores, and grocery stores, Amazon customers can now use the large metal lockers as a way to return unwanted goods purchased through the online retail giant. 

Over the past several years, Amazon has used the lockers as a convenient option for purchase pickups (using a passcode system) when customers aren't home for deliveries, and now it is allowing customers to drop of unwanted items for return as well.

The cost of logistics for a service like Amazon is through the roof and returned items are a very common thing in the online retail world. Amazon spent more than $8 billion in fulfillment across 2013 and nearly a third of online purchases get returned, according to some estimates. With UPS carriers already visiting the locker sites for deliveries, some have suggested the service could bring Amazon's costs down.

Customers are able to get similar services through local UPS sites, but Amazon feels "Customers like the added convenience." It looks as though Amazon is charging the same fee for returns whether its through UPS locations or lockers, so it appears to be an entirely location-based convenience. As Amazon expands its warehouse locations and locker system, Google is believed to be scaling back initiatives of this type after it announced the shut down of locker service BufferBox earlier this year.