Bicycle One has a good selection of high-quality bikes and accessories. The customer service is good, and the staff is knowledgeable. It's not like buying a bike at Wal-Mart. (I don't think they even carry Huffy...) The shop is located in the old part of Gahanna that is being renovated. Aka "Olde Gahanna" (yeah, cheesy).
They have a classifieds section on their website - click the "link" below.