Audi A8 and Bentley Arnage and BMW 7-Series and Mercedes-Benz S-Class

No matter what car you buywill start depreciating from the moment you turn the ignition key and roll out of the showroom. Of course, not all models lose value at the same rate. But there are some cars that stand out more than others and Popular Mechanics has compiled a list with some of the most heavily depreciated vehicles in the luxury car segment. And while this may not be the kindseller wants to hear, it's music to the ears of buyers in the market for snazzy set of wheels. Just remember that regardless if the car is new or used, running costs remain the same, and when it comes to luxury models, be prepared to dig deep into your pockets. 
James Bond is a timeless icon. He looks ultra-cool whether in shorts or a tuxedo, he never cracking under pressure, he has women lining-up for him all over the world, and drives some of the best cars around. But since chances are you'll never manage to get in her Majesty’s Secret Service or obtain an MI6 license to kill, the next best thing is the car brand identified with the world’s most famous secret agent
Pricey classic are out of the question but the mass-produced DB7 from the early ‘90s is an extremely good-looking and cheaper alternative. Never mind that it was based on the Jaguar XK8 platform. – absolutely gorgeous and under the hood you'll find either a supercharged six-cylinder or a V12. Recently, a 2001 top of the line Vantage V12 with just 32,000 miles, sold for $32,000 eBay. Just remember to order your martini shaken, not stirred.
Audi A8 audiwas never really a contender in the luxury-sedan segment until it launched the all-aluminum A8 with its revolutionary
spaceframe in 1997. The A8 offered Audi a credible rival to BMW and Mercedes-Benz.
But despite its technological breakthroughs, the A8 depreciates faster than you can say “Audi” due to high repair costs and a lack of its rivals cachet. For example, a 2001 model with 116,000 miles sold for less than ten grand, $9,000 to be exact. Newer models don't fare much better: an $80,000 (when a new) A8  from 2006 commanded just $26,000 on the popular online market site.
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Bentley ArnageIf is too vulgar for youostentatious,is your brand. The four-door Arnage used to be the top model in Bentley’s range and was offered with either a BMW sourced 4.4-liter V8 or the (preferred by traditional customers) long-lived 6.75-liter turbocharged V8 which produced tremendous amounts of torque.
Pricing when new (that is, from 1998 until 2009), started from around $200,000, and skyrocketed when you ticked a few options. Nowadays, you can get your hands on 2000MY Arnage 6.75 V8 for just $40,000. Just bear in mind that, if you have to ask the cost of maintenance, then you probably cannot afford it
  
BMW 7-Series
The flagship sedan model of BMW's lineup tends to lose value pretty fast because of its high initial prices and even higher running costs –especially if it has high mileage.
A pre-Bangle era (and in our opinion more beautiful) 2001 740i with 160,964 miles sold for just $4,900 on eBay. The next model fares even worse because of its controversial looks and the fact that it is packed with an array of pricey to fix electronic gizmos. A six-year-old 745i with only 45,429 miles sold for $20,000. That is less than the price of a new Honda Accord.
Mercedes-Benz S-Class
Mercedes’ finest is the blue chip in the luxury sedan segment. It is a cocoon that isolates you from the noise and bumps of the outside world, offering a large range of the latest gizmos. Like the 7-Series, you get things that you’ll see in mainstream models in five or ten years later. Who could ask for more?
Still, it depreciates heavily. A 2002 S600 with a V12 under the hood and a sticker price of $130,000 when new, now costs almost 10% of that original price: just $16,000. We have no explanation for this drop: is it that even the rich start to downsize or perhaps move more upmarket? Is it that
sedan has become the default choice in the segment, and as a result, there are too many around? Whatever the reason, this would be our choice for a limo.