Self make mailers offer so many benefits. They are cost effective to produce and require the recipient to interact with it ensuring your message is reached by the recipient. Standard shapes are available, but a bespoke idea could be created to suit your campaign. Popular bespoke ideas are a Christmas or summer survival kit, or pop out and make up Christmas tree and branded product shapes. Decorative or special papers can be used to add to your theme, along with decorative finishes like glitter, spot UV or foil. Why not encourage social interaction with your self make mailer, asking people to tweet a pic of their made up item with a special hashtag. Maybe offering a small prize for the first 20 or the best picture.