Our matching products feature helps you find the coordinating reply card to your chosen wedding invitation design. The reply cards or RSVP cards should be included in your wedding invitation mailing. So make sure it is smaller in size to fit in your wedding invitation envelope. It provides an easy way for your guests to mail back a response to you. Then you will know whether they are attending your wedding, how many guests in their party will be coming and sometimes their meal choice. Reply cards can be in the form of a flat card with an envelope for mailing or a postcard.Zazzle, the printer, provides plain white envelopes with the flat card RSVPs you order. To address these with your return address you can purchase address labels to match. Don't forget to check out the fabulous customizable matching postage stamps you will need to pre-pay the postage for your RSVP envelopes.Order all your items at once and receive discounts from our printer. The Zazzle volume discounts apply per product type. If you order 100 wedding invitations, 100 reply cards and 100 reception cards and the are all of the same type of product, in this case "flat cards", your volume discount will be based on the 300 you ordered.