Your publisher may ask you to give some readings in order to publicize the new book better, or you may be invited by places or organizations that are already interested in the work.
If your publisher is sending you out, expect only minimal payment, if any. Mostly, your travel and expenses will be covered.
DVICE. At the start of your career, with some luck readings will occasionally come your way. You'll get paid for some of them, probably in the $50-$500 range, but you'll also do many for free.
Remember, however, that readings are not simply about money. At their best, they speak to the whole idea of why we write to begin with--to say or give something to somebody else.
DVICE. We would hope that our books would do this job on their own. Of course, they do, but there's more to be said about what a public reading has to offer as well. It is useful to ask yourself what it is about readings that you yourself like most. Whatever the answer, do that when it is your turn. And, at the other end of the spectrum, if you truly don't like readings, then don't give any. Create more of what you like, not what you don't like.
Creating more of what you like also goes beyond simply the reading of one's work. If you go on to give readings, the issue extends to include the persona issue--that is, how are you going to behave? We all know the terms I'm implying--prima donna, star, or whatever. I'm not going to lecture you about this, but you've got some choices to make in all of this, choices with honest consequences. There are other terms worth throwing into the mix--genuine, moving, authentic. Nice. Choose well.