Final answer:
Aluminum is an inexpensive, lightweight, and strong casting material that is commonly used in various engineering applications.
Step-by-step explanation:
The type of casting material that is inexpensive, lightweight, and strong is Aluminum. Aluminum is a commonly used material in casting due to its low density and high strength-to-weight ratio. It is often alloyed with other elements such as silicon, copper, or magnesium to enhance its properties. Aluminum is widely used in various engineering applications, including automotive parts, aircraft components, and consumer products.