Gah, it still depends. During the paranormal craze if you wrote a paranormal novel you could get a higher advance than just a contemporary for instance.
For a debut, looking at a number of recent deals, I’d say that the average YA novel advance to a big six publisher falls somewhere around $20-25k. I could, though, be a bit on the high side. And don’t forget that money could be paid out over 2 years. You don’t get it all at once.
Some books make less and do very well. Some books make more and don’t.
I love money. I do. And I have to sell books to make money. But I also have to throw out this disclaimer and say that no one gets into this for the money. We love books. The money is a bonus. But the majority of authors also have another job.