If you want a used car to last to the 250k point, then the maintenance history of that car is FAR more important than the make and model of the car. All too often, naive people seem to think that they can buy–for instance–a Toyota or a Honda, and that it will be invincible. In reality, a poorly-maintained Toyota or Honda might not make it past 100k miles without huge repair bills unless it was properly maintained by its previous owner(s).
Also–since you didn’t give us any actual parameters such as size of the vehicle, sedan vs SUV, expected mpg, etc, it is difficult for anyone to recommend cars for you.
My recommendations are:
Go to a large news stand and buy a copy of the Consumer Reports Used Car Buyers Guide. This has a wealth of information on every make and model of passenger vehicle that has been sold in the US marketplace over the past 10 years or so, including historical reliability data and recommended vehicles in every price class and size class.
Disregard “clean” Carfax reports, as these tend to omit more information than they include. A so-called “clean” Carfax report can accompany a car that has been wrecked and rebuilt, or a car that has never had its oil changed. That is how unreliable those reports can be.
After educating yourself via that CR publication, begin looking for used cars that come with full maintenance records. Do NOT take anyone’s word for a car’s maintenance history. In most cases, this will push you in the direction of private party sales, rather than used car lots. When you have located a vehicle that fits your needs and that has evidence of being properly maintained, then you need to have it inspected by your mechanic, prior to purchase. This inspection can catch undisclosed collision damage, as well as developing problems. Expect to pay ~$100 for this type of inspection.
If you do what I suggest, you will be giving yourself the best possible chance of getting a decent used car.