At the dealership
Low trade, big discount shuffle
A generous-looking discount funded by lowballing your trade.
What to say
“I have an outside offer of $X on my trade. Let's keep the trade and the car price separate.”
What it is
A store can advertise a large discount on the new car while quietly undervaluing the trade-in by a similar amount, so the net cost barely moves. Because the two numbers are presented together, the shuffle is hard to see. Valuing the trade independently (with an outside written offer) and negotiating it separately breaks the trick.