Joshua Gallo of Los Angeles loves breeding and caring for a virtual menagerie of big-eyed, brightly colored creatures in an iPad game called "Tiny Zoo." The online game is free to download. But almost every week its producers release a new batch of cute animals for sale, including the Cash Cow. Joshua, 8 years old, couldn't resist and ponied up $50, almost two months' allowance. Inside San Francisco headquarters of the game's developer, TinyCo, a printout tallied proceeds from a few days of Cash Cow sales. The total take: about $50,000, according to Chief Executive Suli Ali.