Car dealership financed more than promised price?

[kaja]

SO, my husband works offshore and when he was home last time he bought a vehicle! Well he was really rushed it was a saturday and he had to leave on monday to go back to work. He was the last person at the dealership and they were closed so everything was really rushed! He told me i needed to go and pick up the paperwork because something did not seem right. i went and got it yesterday and i told him the amount that was financed and he said it is not the price he was promised it it is actually 8,000 more! Yes WOW!! Is there anything that he can do since he did sign the paperwork! I did question him about this and he said he was in the mans office and was showed a price and was told it was his bottom line price, he agreed and was told they were going to start the paperwork. he went to get all of the stuff out of our vehicle to trade and when he got back they went over a few things briefly and then he signed it! I told him technically they don't have to do anything, am I right?