Bmw timing belt question. is putting in a new propeller (Drive) shaft the same as changing the timing belt?

I'm a little skeptical of a car that's in "mint condition" that requires a new drive shaft(prop shaft)-unless it had major damage somehow- the only thing you do to prop shafts(usually) is replace the U joint bearings-as far as timing belts -yes approximately every 50-75 THOUSAND miles they should be replaced-just part of maintenance -if it were me and I knew nothing about automobiles I would take the car to a trusted mechanic and have him/her check the vehicle over for the things you mentioned