If neither cyan or black is the color of your choice when it comes to the Lumia 900 on AT&T and you’re interested in the white version you can go ahead and purchase one from AT&T for $99.99 on a two-year contract.
However, if you want to grab the same phone in the same color for $49.99, you’ll need to be a little patient. The device is indeed listed on Amazon with the price mentioned but it currently has a “backordered” status. This could either mean that it sold out like hot cookies or that the listing is already there but there are no phones in stock. If the lower price is important for you make sure to check back with Amazon and see when the status changes. Meanwhile you’d like to read our AT&T Nokia Lumia 900 review if you haven’t done so already.