Offers Less than Book Value on Trade in

Very strange that two NISSAN garages in the same region trade if offers will differ by R50 000,<br> even after I pointed this out the sales rep did not make a better offer, I had a deal done and dusted in a hour just phoning another branch! Group1 NISSAN Kuils River offered 15k under book value and answered the reason for that is they keep extra in case they need to do repairs! this was funny to me since the car up for trade in only had 34700km on the clock with a maintenance and additional cosmetic plan!