Carphone Warehouse are selling the Nokia 520 for £79.95 ($121) as a PAYG (pre-pay) upgrade offer, a £20 saving over the standard PAYG pricing. The upgrade offer is available on four out of five of the major networks and it's worth noting that Carphone Warehouse typically supplies SIM-free (unlocked) handsets. In order to qualify for the offer you will need a PAYG account in good standing, which usually translate to an account that is at least six months old and has a regular pattern of top-ups.

The pricing is the lowest we've seen for a Windows Phone 8 device in the UK. We've previously noted that the pricing difference between the Lumia 520 and Lumia 620 made the latter a better buy. That was primarily a result of a combination of launch pricing for the Lumia 520 (higher price) and special promotions for the Lumia 620 (lower price). As thing currently stand the Lumia 520 is significantly cheaper than the Lumia 620 (£149.95 PAYG upgrade with CPW), arguably making the Lumia 520 the best value for money Windows Phone 8 device.

The Lumia 520 does achieve this status by cutting a few corners, the most notable of which are the downgrading of the screen quality and the absence of front facing camera, compass sensor, NFC chipset, and camera LED flash hardware. The hardware omissions may be a compromise too far for some, but for others are perfectly acceptable in a device that, in the UK market at least, currently costs almost half the amount of the next phone in the Lumia line up.

Here's the conclusion to our Nokia Lumia 520 review:

Taken holistically, though, the Lumia 520 is still cracking value for money, in terms of the future proof operating system, the built-in Office suite, the mapping and navigation services, the 150,000 third party applications available in the Windows Phone Store, and (as highlighted above) even the built-in camera.

The more Nokia push Windows Phone down into this price territory, the better it will do, I suspect - budget Android phones tend to be slow and clunky, whereas the 520, on the whole, flies. And with greater sales at the budget end will come marketshare increase and revenue, increasing awareness further up the price spectrum. Assuming that Windows Phone continues to grow, I suspect we'll be looking back in a year's time and realising just how much the Lumia 520 and 620 had to do with the ecosystem taking off across the world.