As a friend pointed out to me earlier today, there is a huge difference in asking to speak and being asked to speak. If you are asked to speak at a conference, then there should be some compensation. If you are submitting a proposal, you might expect less in the way of payment. I would.
I like how Information Today cares for their speakers. If you speak at one of their conferences, they wave your registration. A nice gesture that, for many of us, goes a long, long way.
–Jane, money always makes people irritable