Customers often return new and refurbished items to retailers because of buyer's remorse. Before these items can be resold they are examined to ensure they works properly.
Usually, returned items in new condition will be reshipped in a regular retail box, but some will come repackaged in a plain brown or white box.
Refurbished returns are typically repackaged in a generic box, but sometimes the retailer obtains retail packaging for the return. The retail packaging may arrive slightly distressed due to having been shipped a couple times.
Some of the best deals can be found on open box items because the price you pay is much lower than the retail price.