i got one as an on-call staff member...i believe you are supposed to wear one if you are working there, ask the manager at the counter you are at most often maybe?
Its part of the uniform for permanent employees. Freelancers don't get one. Sometimes a manager might give one away, but its not usual that they are given to freelancers.
i don't think it's usual for freelancers to get one either.
I'm a freelancer, and My manager had a ton of extras, so she gave me one on Saturday.
I was soooo pleased. Makes me feel so official... one step closer to getting permanent...