Some economists believe that there are goods that do no obey the law of demand, because the demand for them would actually drop if their price fell.

One example is a top-of-the-line luxury car.

Why do you think prospective buyers might feel differently about these goods?

The goods are termed Giffen goods. Normally, the higher the price of a commodity, the lower the quantity demanded, and the lower the price, the higher the quantity of that same commodity.

The higher the price of a Giffen good, the higher consumers will demand it, thus, violating the law of demand. If the price drops, prospective buyers might feel the commodity has become inferior and might purchase a close substitute of that commodity, though, substitute goods are quite rare.