[patio11]

Softbank (Japan) will buy it back from you. Yesterday they gave me $240 (structured as $10 a month for 24 months as a statement credit) for my iPhone 4S. (http://www.softbank.jp/mobile/campaigns/list/tada-kisyuhen/) Generally they're rather less generous ( http://www.softbank.jp/mobile/campaigns/list/shitadori/ )

I assume that Softbank processes 10,000 of these at a time and then sends them to China for resale.

[justinnoel]

$240 is a good price for a used 4S! Now I'm thinking how can they afford to do that so?

[patio11]

I assume that a portion of the calculation is "We got him to switch from a $60 plan to a $90 plan to support the iPhone 6, so rebating him $10 a month is not a hard decision."

[mseebach]

Depending on which discount rate you use in your NPV calculation, it's a good deal less than $240. Also, if softbank are like mobile providers in Europe, it's a $10 credit on the most expensive plan with everything and the kitchen sink included - not the smaller tier or pay as you go plan that's actually plenty for most people.

Also, $10/month (well, less, depending on what the iPhone is actually worth) doesn't seem to be totally out of whack for a short term promotion to grab some market share.