On eBay recently, there were two iPhone prototypes: an iPhone 6 and a first-generation iPhone.
The iPhone 6 is an unmarked model running SwitchBoard, with a red Lightning connector. It’s listed for auction at $2,000 and for immediate purchase at $7,500.
The first-generation iPhone is more interesting. Firstly, it’s a 4GB model running SwitchBoard with a silent button that doesn’t resemble the final version. Additionally, the seller warns against something I talked about in 2014: the possibility of installing an alpha firmware on a commercial iPhone to make it appear as a prototype. He explains that this can be detected by the serial number, which is referenced on fake prototypes, as well as on the startup logo: an on a modified iPhone and a cogwheel on a real prototype. According to eBay, this prototype sold for $12,000.