Salespeople or con artist

I've been contemplating changing my motor vehicle. So it drives me in the direction of motor vehicle dealerships only to find out what a bunch of conniving con artist motor dealer salespeople are. They will offer you very little for your asset in order to maximize their profits both ways....on your trade in and on the new vehicle. I drive a Landrover Discovery Sport SD4 SE with extras that I had to pay for that is of no benefit or makes no difference to the trade in value. The vehicle is in great condition and is a pleasure to drive. To be honest I love the vehicle but thought of maybe getting an Evoque to replace it. There is nothing wrong with the vehicle everything is in great condition even the interior looks new. They also want to sell you a vehicle with all the bells and whistles that you have to pay extra for but also does not add any extra value when trading it in. They offered me way below trade value with the reason being that there is not enough profit built into the new vehicle I want to purchase.(does that make any sense) The manufacturer has a build your own vehicle on their site but the dealers try to sell you anything besides what you want. Then there is the other thing I take the same vehicle to a different manufacturers dealership and I am offered R120,000.00 more for my vehicle on a trade in. The dealerships use Transunions trade in guide (which is really only a guide) as if it's the know all of the trade but it is skewed in favour of the dealer network. Makes you think right is someone out there trying to con me?