Give contact cards. I have seen people selling in expos nothing to do with food, like home building or decorating. There is always a pair of stands selling cupcake deocrating clases or selling cookies, cupcakes and coffe. Near christmas or child day so many people goes to toys stores, then near the stores pople park their cars and sell cookies packed to give as a gift. I don't know if that can be posible in your country.
other ideas are macaroons, choux, ecleirs, small pies, desserts for tables, and fresh friut in sticks, salt goodies too! like small sándwiches,