Apple no longer sells the iPhone 5S. Though you may still be able to scoop one up new or used from a third-party, you're better off buying the iPhone SE, the least expensive model in Apple's current lineup, which starts at $349, £265 or AU$465. That noted, if you can hold out until September, it's highly likely that you'll have a new batch of iPhones to choose from as well as lower prices for the iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X and perhaps the iPhone SE -- if it's not discontinued or updated.