Calculate the value of a used Samsung Galaxy S3 by using a valuation tool on a smart phone resale site such as Glyde, Flipsy or Gazelle. Values are also available by checking current listings for the same model of phone in the same condition on auction sites such as eBay.
The three biggest factors in determining the resale price of a used smart phone are the model, carrier and capacity. As Samsung continues to release new phones in the Galaxy line, and introduce new lines of smart phones, the Galaxy S3 decreases in value because its specifications become overshadowed by newer, more powerful models.
The carrier is also important because certain carriers offer better coverage in different areas, or no coverage at all. An unlocked smart phone, which can work on any cellular network, sells for more than one tied to a specific network for the same reason. The capacity of a phone also matters, because phones with bigger amounts of storage space are more desirable than those with smaller amounts.
Smart phones are similar to computers in that they depreciate in value quickly due to advancements in technology. As such, a Samsung Galaxy S3 should be sold as quickly as possible to decrease the gap between it and the latest model.