Don't be frightened: When you first walk into Gumballs after picking your way through a jungle of plastic trikes, wagons and other yard toys parked in front, it's a little bit frightening, like entering the remains of a trailer park ravaged by spring tornadoes. But step lightly over the shoes piled up in the aisles, and be brave: The stuff's there, at least what's in season, from frilly Easter dresses to swimsuits and leotards for little water babies and dancers. It's all used, accepted on a straight fifty-fifty consignment deal, and though it's tightly packed on the racks, there are plenty of clean and pressed treasures to be unearthed. Such as: sweet frocks from Baby Lulu and Biobottoms, an entire rack of secondhand Gymboree duds, Disney videos and a painted wooden Babar rocker that could be the centerpiece of any well-appointed nursery, all at prices well below what you'd pay for them new.