Luxury is a relative term and it does not always just refer to the premium brands. Luxury could simply be any car that you happen to want, despite its price. For example, some car models may be more expensive than others, but very attainable under the right circumstances. So the experience of getting any high-end car could be a luxury, too.

Kelly Blue Book value is among one of the best online resources where you can find information on luxury cars and other types of vehicles in the category.