Auctions can be pretty addictive and when luxury cars are on the block, many have to watch out for their competitive streak. You wouldn't want to end up paying millions for something just because you didn't want that pretentious man with the monocle to win. If you happen to be at the auction that includes a 1955 Mercedes-Benz 300SL Alloy Gullwing though, knock that monocled man over if you have to.

The Gullwing, estimated at around $5.2 million and one of only 29 300SL models with the alloy body, will be among many cars and motorcycles auctioned by RM Auctions in Battersea, London, on October 31, 2012. Not sure why they went with Halloween as the date but I'm sure you can come up with some sort of costume that fits with the collectible car's gull-wing doors. Maybe a secret agent with a penchant for shiny red interior?

Also up for auction is a 2008 Bugatti Veyron EB 16.4, which has a top speed of over 250 miles per hour and only 435 miles on the odometer. RM Auctions is hoping the fast car will bring in at least $715,000. According to Adrian Hamilton, chairman of Duncan Hamilton & Co., the Veyron is a pretty pricey car to own since you'll run out of gas in 16 minutes if you drive it full speed. Hope you're a Texas oil tycoon because otherwise it's going to be a tough car to maintain.