I ordered some business cards a couple of months ago with our STD info on them (250 for just the cost of shipping). But the more I thought about how much we were going to have to spend to get the magnets and envelopes for them, the more I wanted to do a postcard.
This is the original STD. I really liked the design when we first made them.

And this is our new (and improved) Save the Date!
Front side:

Back side:

I'm so pleased with how these turned out! And I'm happy that we didn't lose too much money on the old ones!