"If you are going to ride it elsewhere, maybe you should check that place's market, as it probably will be cheaper and easier"

Do you mean i can just buy a plated bike where ever and ride it legally? I thought i had to transfer the plate to my name and that this would only be possible at my place of residence. Guess i still haven't understood everything about the plates/registration ^^ Is the plate registered to a specific vehicle AND a specific person or just to the vehicle? (I mean, in terms of surveillance, speed traps ect registering a plate to a vehicle only wouldn't make much sense)

As said before, i actually don't want a bike for within beijing/daytrips around beijing but for a longer tour to experience some other areas of china. So it doesn't make much sense to buy anything here for me.

The more i try to learn about buying the more problems i see, i guess i better stick to the inital plan of renting :D Thank's for your hints on transfering plates in beijing though anyway.