Keep in mind that the first 3 cars are Premium cars, so everyone can buy these cars from the OCD and therefore not interesting, sorry about that, just saying.
The only car suitable for trading will be only the Mini or cars from the OCD (in 0/0/0 condition).
Yes, sure ... but the money issue rises when the car is more than 1 million or more.
If people do the seasonal events, then get instantly enough credits to buy such cars.
Besides that any Premium car is always in 0/0/0 condition too.