Custom Stamp Gift Set, available on Paper Source, $29.95
Planning a wedding includes quite a bit of snail mail — invitations and thank-you notes, for starters — and a custom stamp can make the process go by much faster. Each gift set includes a self-inking stamper, one black ink cartridge, and one gift certificate that allows them to customize a stamp plate online.
If you've got a bigger budget, there's a beautiful copper version on Food52 from $185 as well.