The Simple Postcard - Text a photo to mail it as a postcard
Stocard - All loyalty cards on your smartphone!
Felt for iPhone - Handwritten cards for the modern world
Pass2U Wallet - Put cards into Apple Wallet
Send Mail Get Mail - A postcard-sending website.
PayPal - PayPal is the faster, safer way to pay online without sharing financial details, send and receive money or accept credit and debit cards as a seller