The illegal puppy trade is booming: Young dogs are brought to Germany from Poland, Bulgaria, Hungary, and Slovakia to be sold at rock-bottom prices. A purebred puppy can go for as little as 300 euros instead of 1,000 or more. “But people only think it’s a bargain,” says Christa Thöne-Reineke, a professor of animal welfare, animal behavior, and laboratory animal science at the Department of Veterinary Medicine, Freie Universität Berlin.