Use a post card as your Save the Date or Response Card or for informal invitations for parties and save money on postage.
Privately manufactured mailing cards, called postcards, were used as early as 1870, but initially required the same postage as a letter. A special rate for postcards came in 1898. A post card, which is $0.28 to mail, has the following size limits:
- Minimum: 3-1/2 inches high by 5 inches long by 0.007 inch thick
- Maximum: 6 inches long by 4-1/4 inches high
- Additional postage required for larger postcards