This was a fairly simple inspiration to execute.
On the back it says, "Send and ye shall receive."
Sent to a work colleague.
If I was Australia Post I would have these die-cut. Could maybe even do the logo that way too. Letterpress messages on the back like, "Show you care. Write to Grandma." Give it away to school kids when they check out the GPO. Plenty of ways to rustle up business.
Don't forget the magic of mail.