In honor of Maryland's official Diamondback Terrapin Day, Diamondback Trading Cards is offering a two for one deal on all sets of trading cards sold until midnight tonight. Buy any set and get any additional set for free. Sets can be different, use the comments field at purchase to designate which set you would like as your free set. This deal applies to regular sets and Collector's editions. Any set purchased gets a free set of your choice, period.