They charge anything and everything they can. They charge you "Document Preparation Fee". i.e.they charge for their time to fill out paperwork to sell you the car. I would ask what specifically that is, it's vague and you are entitled to know what is costing you $700 of your hard-earned money. When I bought my car I called them out on that, the Document prep fee, $50, and of course, "oh, i will have to ask the sales manager" 10 minutes later, after they talked about the ball-game last night, I got "Well, Mr. ..... We are going to do you a big favor. We never do this, but will waive that, you seem like a nice guy" Oh lord, gimme a break. Only reason the waived it is because I told them flat out I'm not paying it. No deal otherwise. But not knowing what it really is, it may be a legitimate fee. But like I say, for $700 you are entitled to a full explanation.
I never pay the documentation fee. I tell them to take it off of the deal or I walk. They usually lower the price to cover the fee.