Dry skin means lack of water, not lack of oil. Skin creams function by creating a temporary barrier on your skin that seals in water.
In the late 1940's, a doctor at Massachusetts General Hospital took a hard callus off the foot of one of his patients and placed in oil. It remained as hard as ever. Then he placed the callus in water and it became very soft, but soon after being removed from the water, it became very hard again. Then he left the callus in water until it became soft, removed it and then soaked it in oil and it remained soft for a long time. He had shown that dry skin should be treated by using oils and creams to seal in moisture. Cosmetic manufacturers soon produced oil-in-water emulsions which were incorporated into creams designed to seal in water.
However, some studies show that oil-in-water emulsions soak off the outer layer of skin and increase its susceptibility to irritation from cold, rubbing, and various chemicals that you may be exposed to, such as ingredients in cleaning products or cosmetics. The longer skin is immersed in water, the more protective outer coatings of skin is stripped off. Take quick showers and decide for yourself whether using a cream or lotion helps you or not.
All lotions and creams work the same way, no matter how much they cost or what special ingredients they claim to contain. Just pick one that feels and smells pleasant to you.