In the US... What puck posted is the price for the Full Maintenance upgrade, which covers regular services (oil change, inspection, brake flush, pollen filter, etc.) and wear-and-tear items (brakes) only, but does not cover repairs as it is not a warranty. BMW offers the Original Owner Protection Plan which extends the 4/50 warranty to a 6/100 warranty, and is *completely separate* from the maintenance plan. Most dealerships sell the Full Maintenance upgrade, however, many do not sell the Original Owner Protection plan. The price on the OOPP is steep.
Most dealers would rather sell you an extended warranty from a third party, which will cost less, and still earn them more profit. However, any plan that is not backed by the manufacturer is probably not worth purchasing. For more information, go to the Edmunds boards and do a search for Warranty Gold.
You have until the 4 year/50k mark to decide whether or not to purchase these plans. The only risk is that the price may go up. There is also the risk that you will sell the car before the 4/50 plan is up, and although you can transfer the plan to the next purchaser if you sell the car privately, it have little effect on the sales price of your car. I plan on waiting to see if I keep the car that long.
Based on my own past experience, I don't recommend that most people continue to own a European car past its warranty period. Your mileage may vary--pun intended!