My two cents...I've worked at nonprofit organizations for years. I've also been approached by dozens of groups to speak at their functions. In my "old" job my time was covered by grant money but now that I am on my own, as a consultant, it isn't. I am moving away from free speaking engagements and moving away from the guilt (I enjoy helping underprivileged students) and truly only accept events that are mutually beneficial. Some people will say, "But you can promote your book!" Yes, but what about being out of the office (billable hours for me, time away from clients), daycare for the kiddies, travel, etc. There are no easy answers but selling twenty books is not going to cover my expenses...let's see that might be about 20 bucks. Okay, enough negativity, here's my positive outlook:
The book might get me in the door but my expertise is worth a lot more. I counsel nonprofit managers on how to develop their programs, I help donors design good scholarship programs, I assist schools in reaching out to scholarship sponsors. Yes, my book is about helping students win scholarships but my expertise is far beyond that. For Greenwolf and others, why not start pitching your expertise (not your book) and as Billingsgate said, at minimum, have a bottom line policy. Airfare, hotel, food, parking/transit and a speaker's stipend - they do not have to know that you are using it to pay for daycare and if I were you I wouldn't mention that...it's irrelevant. Whether you are single, married, have kids or not, you should be compensated for your time...unless there is a mutally beneficial reason for you to be there. In business, this is called opportunity cost. You go for a low rate because the opportunity to meet certain people, close a deal, etc. outweighs the cost. At minimum, your basic costs should be covered and you should not go in debt just to attend the event. I have presented at many wonderful events and because I was a member, my employer paid for it. That was part of my professional contribution for the year....however, like I said, I am now self-employed and that is not financially viable option.
Another idea is to ask if there is a potential sponsor who has an affinity for your subject. Suggest that they find a sponsor for your session. In the program it could say "sponsored by....."
I only offer this advice after doing hundreds of workshops and seminars and the lessons I've learned.
I know it's very flattering to get those phone calls but think carefully about the opportunity costs (time, money, missing family) and benefits (networking, connections, credibility, etc). Good luck!