No less than letterpress, her save-the-dates were made by an actual poster company in Nashville, Tennessee, called Hatch Show Print. This particular print house has items in museums and they make posters for greats such as Bob Dylan and Bruce Springsteen. Even with all of their fame, her letterpress save-the-dates came out to something like $3.00 a piece. Yes, pricey, but not so bad for letterpress. And, they are completely unique.
Did you do anything out-of-the-box and completely unique for your stationary?