well my go to items for printing and giving away are hollow trolley tokens ( also work in gym lockers that take coins, basically a narrow rimmed ring the size of the relevant coin) And a trolly key.
Trolly key is A half coin on a stick with a hole to put on your keyring.
Easy thing to design and make , usefull, fast to print and needs to be exactly the right size to work.
And trust me, you can never have too many of either :-)