Went to buy a 2nd hand land rover last year, deal was done on the price then they said it would be £199 additional to pay for preparation of the car!
I argued a toss with the sales guy that is ridiculous, I even said was more than happy to take the car as it is so you can wavier the fee.
They refused to back down off the £199 fee so I told them to lump there deal we are no longer interested and walked away. In the grand scheme of things it's a very small percentage and really insignificant compared to the cost of the car but it is the principal of it that annoyed me.
Nissan sound even worse from your experience