No offense to Once Upon A Child, which offers junior's gently-used with sure, if bland, efficiency. But shoppers looking for surprises in selection, not to mention price, might consider regular visits to the Unique chain. Regular because, as at most thrift stores, you have to be there to stumble on finds like brown suede Hush Puppies for four Georges or a handmade '60s red corduroy toddler girl's coat trimmed in white rickrack. Of course, neither of those items will ever be found there again. But unless you're ready to spring $14 to $28 for vintage children's shirts, sweaters, and dresses at the very fun Oh Cool Baby store in Nordeast, Unique is the place to discover unexpected and one-of-a-kind used kids' clothing, on the cheap. Unique can also be depended on for better brands like Oshkosh, Circo, and the Gap--all at a more than reasonable price. Even better, everything is 50 percent off on national holidays like President's Day. (And then there was that pair of pristine Stride Rites for five bucks....)