Cuba's cash-strapped government on Tuesday began selling used cars for dollars at a single Havana outlet, a first for the Communist-run state and a further step toward the dollarization of a segment of its retail sector.Around a hundred people showed up to look at the cars, representing a hodgepodge of brands and models. Around one in 20 Cubans owns a car and the cost puts them out of the reach of many citizens, in a country where the average wage is below the equivalent of $100 per month.