Carvana, the online used car marketplace, has agreed to buy Kar Global’s Adesa U.S. auction subsidiary for $2.2 billion in cash, an acquisition aimed at adding another revenue stream as well as a network of physical sites that could help bolster operations.Carvana, the online used car marketplace, has agreed to buy Kar Global’s Adesa U.S. auction subsidiary for $2.2 billion in cash, an acquisition aimed at adding another revenue stream as well as a network of physical sites that could help bolster operations.