At this year's Mobile World Congress, Mozilla is pushing its self-appointed mission to create a truly affordable smartphone with the demonstration of a $25 proof of concept device. Built by chip partner Spreadtrum, it runs the latest version of Firefox OS, but unfortunately does so with considerably more lag than the new generation of handsets introduced by Mozilla's partners. The basic spec is reminiscent of the original iPhone, with a 3.5-inch, 320 x 480 display, 2-megapixel camera, and no 3G connectivity. That's where the similarities end, however, as the Firefox OS prototype uses a quite terrible LCD display and offers a maddeningly slow user experience.

These sacrifices may appear justified by the device's rock-bottom price, but they also place a question mark over whether it can really be considered a smartphone. You can access YouTube, take pictures, and browse the web on it, but the phone's responsiveness is so sluggish that you probably won't want to do any of those things.

Cheap, but not cheerful

Aimed at the most price-sensitive segment of the smartphone market, this $25 prototype wants to bring the capabilities of web and email access to those who can't afford even Nokia's entry-level Asha handsets. It has room for a pair of SIM cards, and though its physical design isn't indicative of what retail units will look like, it's built to a reasonable standard. The hardware platform could scale lower, too, with options of 2.6-inch QVGA displays allied to a BlackBerry-esque QWERTY keyboard. In essence, these are 2014's bargain-priced recreations of 2007's best phones — or they would be if the user experience weren't as disappointing as it is today.