Anyone know where you can buy an iPhone 6 for cheap? I'm talking $300 to $400 factory unlocked too?

My boyfriend has an HTC and they battery literally does within 30 minutes. Horrible. He needs a new phone I got him the IPhone 3 a few years ago but over the summer he jumped in a lake and it was in there. But anyways that doesn't matter. He likes the iPhones and I like them as well. But he really needs a new one. So does anyone know of any websites I've looked around but most are like $550 and stuff which I'm not looking to spend that much. I've seen a couple for $350 and they have told fast or the people like out of state

Read more: Anyone know where you can buy an iPhone 6 for cheap? I'm talking $300 to $400 factory unlocked too?