This happened to a younger colleague of mine. It was one of the first sales she made, but it was a doozy.
She discovered a well written urban fantasy novel.
She received an offer of one book for $6000. Okay, it was modest, but it was something.
Then someone else made an offer for three books for $10,000 each.
Competition set in and the amounts continued to climb. Some publishers dropped out when it became more than they wanted to spend.
This kept going until there were only two publishers left. One of them got on the phone with me and remarked that the young agent had a tiger by the tail. I could tell she was surprised. She thought this would be easier, and that she could snap this up for little money. After all, the agent was a beginner and so was the author. I smiled and replied that yes, she was doing very well.
The auction ended after three days at three books for $125,000 each. A far cry from the opening offer of $6000 for one book. All three books made the NY Times Bestseller list.
I love this story because it shows that you should be ready for anything. You might be bitterly disappointed, or you might get a lovely surprise, but anything is possible. You never know what the day will bring. But the bottom line is that the agent was very well versed in the genre. She knew exactly how good the material was–and how valuable. She was going to let the market dictate the price, but on her terms.