Deal: Get a refurbished Apple iPhone 6 Plus for less than $200 at Walmart
If you want to purchase a refurbished iPhone directly from Apple, the cheapest you can get is the iPhone 7 priced to sell for $470. However, if you want to buy an even cheaper iPhone, you'll have to look elsewhere like Amazon, Best Buy, Newegg, Walmart, and other authorized retailers.
At the moment, Walmart is running a promotion on the refurbished iPhone 6 Plus (64GB), which is now available for just $190. Usually, such a device sells for at least $225, although most of the time you'll find it at $250.
Just make sure to select the Silver/White version of the iPhone 6 Plus, not the Gold/White or Space Gray/Black models which are more expensive. You'll also be getting 2-day shipping for free, but you'll have to hurry since there aren't too many units left to sell at this price.
There's one important thing you'll want to know before you buy it though: the device comes unlocked and it will work with all GSM carriers (T-Mobile, AT&T, Ultra Mobile, Simple Mobile, Cricket), but it will not work with any CDMA carriers (Verizon, Sprint, Boost Mobile).