is this sentence correct:
If the price of cars were higher every body couldn't buy several cars.
Welcome to the foruum, mahsanvandy
Please try to give your thread a more helpful title. This one could have been, "Everyone couldn't buy?"
Your sentence would be more natural as: If the price of cars were higher, not everybody would be able to buy several cars.
Actually, there are not many countries in the world in which everybody is able to buy several cars, anyway.
Or few would be able to buy several cars.