How many types of caskets exist, and why are some more expensive than others?

Caskets are made of either metal (bronze, copper or steel) or wood, and are available in a variety of styles and colors. Prices vary, depending on the exterior and interior materials used. Bronze, a semi-precious metal, is more expensive than steel. Mahogany, a rare hardwood, is more expensive than the readily available softwood pine. There is also the option of adding personal touches to most caskets.