Hard to say. Some of our members do tell at seniors’ homes, charity events, schools, Guides/Scouts, birthday parties, etc. So it depends on the event and the teller.
Is there a charge? Hard to say. Some charge, some don’t. For some tellers, it's how they put porridge on the table. We suggest that an honorarium is a polite gesture of respect. Some may return it, some donate it to their favourite charity, (includng the GGS), and some may use it to buy porridge and be able to add some raisins.
Details may be under tellers' profile. In addition, don't be afraid to have the conversation. There may be opportunties to negotiate.