1. A system for determining costs of vehicle ownership, the system comprising: a computer processor; a network interface coupled to the processor; a data storage device coupled to the processor; an output device coupled to the processor; wherein the processor is configured to receive information identifying a user-specified vehicle of interest and a user-specified ownership interval of interest, identify one or more pre-calculated data items that are stored in the data storage device and retrieve the identified pre-calculated data items from the data storage device, request one or more external data items from an external data source and receive the requested external data items from the external data source via the network interface, compute a cost of vehicle ownership for the vehicle of interest, and output the cost of vehicle ownership for the vehicle of interest to a user via the output device.