I made these off a design I saw on Etsy and they were super easy to make. I started with a simple postcard template for Microsoft Word and deleted the sample text. Then I did a quick search for a vintage-style fonts online, found a few I liked and played around with them till I found one I really liked. I used a different font for the date, but it all turned out really well!
I'm going to try to print them at home on card stock, but if they don't turn out well I'll just take them to a print store (kinko's or the like).
I'm going to mail them in the envelopes I bought on Etsy, which should be here this weekend! I can't wait! :)