A yoga studio in Washington said Tuesday it will give free classes to anyone who casts his or her ballot in next week’s US elections. Flow Yoga Center said it was throwing open the doors to its Astanga Mysore, Pilates, Prana Flow and Vinyasa Flow classes next Tuesday “to help our United States re-unite again.” “You just need to vote first, and then bring along your ‘I Voted!’ sticker or equivalent to get a free class,” said the studio, in the trendy Logan Circle neighborhood, in an email flyer. Those ineligible to vote can attend classes, too, so long as they buy a “pay what you can” pass for as little as one dollar. Election time in the United States is rife with marketing gimmicks. They include free pizza for life from Pizza Hut, fresh coffee in blue Barack Obama or red Mitt Romney cups from 7-Eleven, and free flights out of the country on JetBlue for voters whose presidential favorite loses.