Baseball Jerseys are good sellers on eBay, especially vintage baseball jerseys in used condition. Anyone can go to a local sporting goods store or shop online and get a new jersey of there favorite team. But people want to look cool and stand out at games by wearing a different jersey than everyone else that shows support for there team.
Your local thrift shop is a great place to find these. Not only do you have the advantage of selling to someone in your area who doesn't want to go looking at thrift stores for items you also have the advantage of selling the Jersey worldwide. Someone living in New York can easily get a new style jersey of there favorite California team by shopping online, but to find a rare vintage style jersey they will turn to eBay. You living in California have the advantage of local merchandise like team jerseys at your local thrift store. Living in New York they will probably find plenty of Mets and Yankees jerseys, but if they support another team they will turn to eBay.
Check out some of these closed listing of used Jerseys, some even have stains on the jersey, so they are not in perfect used condition and they still did well. The bigger the size the better, and popular teams like the Cubs and Red Sox are always good sellers.