Motoring.co.uk's database is the natural home of the best value used cars. This extensive resource lists everything from vast four-wheel-drive leviathans to economical little city cars. Many of these vehicles have depreciated considerably since the original owners claimed the keys, so let's consider a couple of noteworthy bargains.One of the general principles of car valuations is that originally high priced prestigious vehicles with modest badges lose value quicker than a panicking stock market. The Citroen C6 is an excellent example. Back in 2007 the standard 2.2-litre model had a list price of £28,000. This vehicle is now only worth approximately £11,500. The high-spec 2007 3.0-litre V6 Exclusive has also plummeted in value from £36,000 to roughly £13,000. Eye-watering depreciation also affects the Volkswagen Phaeton. Straight from the factory in 2007 the Phaeton 6.0-litre W12 4MOTION (lwb) cost £73,860. This monstrous beast is now only worth a comparatively modest £27,000. That is a drop of nearly £47,000 in three years, or to put it another way - virtually the price of a new Jaguar XJ. The final executive contender is the recently retired Peugeot 607. This Frenchman's plaything may not be particularly good to drive, but it is a good value used purchase. Shiny and new at the beginning of 2009 the top-end 3.0-litre V6 Executive cost a noteworthy £29,000. This model is today only worth a temptingly affordable £13,000. These three vehicles are clear proof that cost conscious bargain hunters can easily source a great value used car.