If you're looking to buy a WP7 device on Ebay, then you better make it snappy. WP Central, with help from Lorenc have spotted an upward trend in the prices of the popular WP7.0 handsets (HTC's Mozart and 7 Pro, and Dell's Venue Pro). Both final auction prices and the immediate Buy it Now prices have seen rises from early September. in the case of the 7 Pro there's been a 45% jump in value.

The measurements, as graphed above, show a steadily increase in price since early September, just when Mango-fever was picking up. The jump in price is also fairly significant, with the 7 Pro going from an average of £240 to £350 in just 30 days.

The market can be a volatile place, but the correlation between the Mango publicity (and confirmation that old devices would get the new software) is irresistible. There's a lot of people interested in Windows Phone, and maybe the Mango news was enough to push them to look for a cheaper way to try the new OS than a two year contract?

More details, and pretty graphs, at WP Central.