Payment may come with a by-line, but don't expect it as a quoted source in someone else's work. Your compensation is the name-exposure and reputation enhancement that come from being quoted. Expert status opens added opportunities for low-cost promotion. If you don't freeze at the sight of a crowd staring at you then you've passed the first hurdle to this high-profile promotion method. One or two handouts and a willing audience are the only other requirements.
Some groups allow speakers to sell their works at the event.
Most permit distribution of business materials. Speaking engagements provide streamlined networking. Some groups pay an honorarium, or more, but many don't and you shouldn't insist on it. The exposure you get is worth your investment of time, providing you address only groups whose members are potential customers for your business. You're making public presentations to gain potential standing orders, not standing ovations.