Dealership trade-ins is very convenient for car owners. No need to look for buyers. Get a credit on vehicle value immediately. But that convenience has a price.
If one is not in a rush, a much better price can be attained by selling the vehicle yourself.
As an example: Back in 2005, I had the dealer assess a 95 Civic ESI M/T w/ less than 60K kms mileage. Dealer offered 90K (trade-in value) which is absolutely ridiculous. Eventually sold the vehicle by myself to a private buyer for 195K.