I have a problem with my audi s8 2000.
when driving, after around 500-700 miles the oil is below minimum!!!!
Is it a normal thing to fill it so often?
or is it a common problem?
the car has no leaks and there is no smoke from the exhaust...

 

Did you just buy the car? Thats definately not normal. If its not smoking its not burning the oil, and if its not leaking the only other cause could be its full of sludge and harnening in the valve covers making it look like the crankcase is empty. Get it checked out immediately! Adding more and more oil could be fatal to your engine.