From Paper Parcel:
PaperParcel.co is a web app designed to make the card sending process simple, fast & easy. With a standard rate of $5 a card, shipping & tax included, the card can be sent to anywhere in North America, with international coming soon. The card is minimal and clean so that the message on it is what stands out. Date stamp on the back, mailed in beautiful stay-flat envelopes, there is no one that won't love receiving one in the mail, be it for any holidays, birthdays, get-well-soons, apologies or a simple 'I love you.'