to put one over on sb

What does the following sentence mean?

..."What? That's awful. I am afraid he put one over on you."
True? Yes, she had told the truth, but few people like to listen to truths that reflect on their judgment. So, being human, I tried to defend myself. I pointed out that the best is eventually the cheapest, that one can't expect to get quality and artistic tasteat bargin basement prices, and so on and on...