I am planning to buy a BMW X 5 2010 with 89K miles, I am affraid of the time belt or chain belt, how much this can cost?

Read this thread, and stay focused on maintenance, I found this for you online, finally, keep your checkbook handy, "BMW timing chains are engineered for the life of the engine and never need maintenance or replaced. To prove that point BMW has always performed several long distance tests on its new engines before they are put on the market. Back in the 90s they took a e34 (5 series) and ran it over 2 million miles, just performing the standard maintenance. When they took apart that engine everything measured to spec. Enjoy your Bimmer and just make sure to get the regular maintenance performed but no need to worry about the timing chain. Now if your a e30 guy like myself your stuck with the single worst decision, sorry second worst (hiring Chris Bangle), Bimmer engineers made and that was to go with a 'quieter' rubber band timing belt." http://mechanics.stackexchange.com/questions/7/does-a-timing- chain-need-maintenance