However, some cities are very strict about businesses having business licenses. Some cities don't enforce it.
If you kept it "small potatoes" then likely the city will not seek you out to try to enforce some license law. Besides, you could claim that you were just getting reimbursed for your hobby expenses, and that it was not a business affair.
The thing to do would be to find out how your city handles it.
If you generated enough income from this, then the state and federal tax men will want to know, but for a "small potatoes" deal, nobody much cares.