Margarine is a butter substitute and has been found to more unhealthy for you than butter. It may lead to an increased incidence of heart disease, cancer, and other diseases. The typical ingredients list for margarine is: "Vegetable Oil Blend (palm Oil, Palm Kernel Oil), Soybean Oil, Water, Buttermilk, Contains Less Than 2% Of Salt, Potassium Sorbate (to Preserve Freshness), Soy Lecithin And Mono And Diglycerides (emulsifiers), Lactic Acid, Natural And Artificial Flavor, Vitamin A Palmitate, Beta-Carotene (color)."

Butter is just churned cream. You can buy whole whipping cream and just whip it with your mixer until it turns into butter.