Chin Up: The new Periwinkle location opened Friday, and to celebrate, everything at both spots is 20 percent off all month. Since the more you spend, the more you'll save, we suggest going all-out -- it's practically making money, right? ...Right? Suzi Chin dresses (were $248, now $198.40) are a great option for all those spring garden parties you'll undoubtedly be invited to, because it's totally 1961, right? The ivory ruffleneck and the purple full-skirt are both gorgeously luxe ways to go retro. GET IT:Periwinkle, 4150 Campbell Ave. #104, Arlington or 1557 Potomac Greens Drive, Alexandria.