• Use recycled or tree free paper.  Or even better, go handmade…or seeded!
• Use postcards as your reply card.  Postcards eliminate the need for an extra envelope.
• When thinking about ribbon, a raw silk (dupioni) is a fabulous option.
• Include as many inserts as possible in your invitation mailing, so that you are not mailing as many separate invitations to your guests.
• A really fun idea for table names (or numbers) is to have your calligrapher write them on a rock or something fun from nature.
• Choose a printer who uses soy-based ink.
• Eliminate paper waste by using extra space on the printing page to print escort cards, tags, etc. that you can use later.
• And recycle.  Please recycle your leftover paper.  Or call up a school and offer it for art projects.  Most preschools or elementary schools would love to get some fabulous hand-me-downs.

Everything Green Weddings has a great section on eco friendly invitation & paper options.