Instead of having formal invitations printed, keep everything light and romantic, and make your own.Template
Photocopy the hot-air balloon pictures on the template (or use a picture of your choice) onto tracing paper, enlarging or reducing it, if necessary. Cut out one picture for each invitation, along with a piece of plain tracing paper to be used as the backing for each one. Machine-stitch the front and back together along the sides to form a small pouch. Fill each packet with heart-shaped sweets and a small piece of paper with all the party information. Close the top with another row of stitching.