The cheaper options on Brown cards come from Minor League sets like the Just Minors and Tristar products. By cheaper I mean that you can find these cards easily for 2 to 3 dollars. I like the Just card since he is pictured in his Oklahoma State uniform. Brown also has an autograph in the 2007 Donruss Elite set. Again, he is pictured in an Oklahoma State jersey. His Tristar autograph features him on the Vancouver Canadians team. It's better than having a blanked out card, but still I like the college baseball cards better. Just personal opinion.
Better option: Find a copy of Corey Brown's 2007 Bowman Chrome Autograph. The card might cost you an extra dollar or fifty cents above the Just or Donruss autograph, but finding autographs out of the Bowman products is rarely a bad thing. Brown's Bowman Chrome autograph is an on card signature and features a nice picture which does not really look airbrushed. Is it? Can't tell.
Brown has one other Major League Baseball card release in the 2012 Topps Heritage set. It's a prospect card featuring Brown as a member of the Nationals. The card also features Michael Taylor, Adron Chambers, and Joe Benson. Again, not hard to find and not expensive to buy. This card usually costs less than fifty cents.
Brown also has several different Minor League team issues. He has been in the Minors since 2007 and has been in Triple A since 2010. Much of his time has been spent with the Syracuse Chiefs, but last season was spent with the Pawtucket Red Sox. Brown has made some brief appearances with the Nationals and Red Sox. As a Tampa native I am sure Brown would be excited to get a chance to play for the Rays this season.