A rust-dappled Hyundai for $3,000, a clapped-out Geo Metro for $5,000, and a censurable Ford Festiva for six grand? Welcome to upside-down world. The rising price of dinosaur champagne has already decimated the large-SUV business, and now the realities of gasoline economics are elevating what was once the lowliest segment of the used-car market into Croesus' territory.

Mass transit systems across the country are experiencing surges in ridership, pushing many of them to the brink of capacity for the first time. As the price of oil continues its inexorable climb—now past $125 a barrel—some metropolitan areas have seen an increase in use as large as 15% over this past year. While cities with integral systems, like New York, have reported a small bump, it is municipalities in which car transport has been the norm which are now overflowing with new subway, light rail, and bus riders.