You CAN but you shouldn't, cause it would make you the worlds most 'cheap' person.
There is a universal system which is trying to be implicated where you name a contact "ICE.NAME" so in an emergency if you have a car crash for example, they have someone to call straight away, look for a contact in the phone like this if you want to do the right thing and return it, alternatively just hand it to the local police, who would probably throw it in the bin.