I am having trouble finding any postcard stamps online, that do not require me to spend extra money to purchase them. USPS only has two, one is a polar bear and the other is a herb. A simple flower, a cake, or something saying wedding or celebration would be fine. I do not need something super fancy, but I do want them to go along with the invitation style. I know zazzle offers ones you can design yourself, but honestly I do not want to spend $18 for $5.80 worth of stamps. We also already have envelopes, for the invitations, so stamp.com will not work either. I need to send out the save the dates by the end of April. Any suggestions?