30% PCW and environmentally responsible inks.
$18.00 for a box of 12 at Redbean

From recycle-eh.com, this a group of 25 recycled Halloween cards. Created from recycled magazines and junk mail, this fun group of cards range in size from 1″ square to about 2″ x 3″ for the largest size. Great for personalizing your “tricks” and your “treats”! Looks like a fun ghoulish eco-friendly mix!
$4.50 at Recycleeh’s Etsy Shop

Every card that you need for an entire year!! …get off the computer and write a hand written note. No guilt with these 100% post-consumer paper cards with cute little designs. The box of 40 cards contains: 2 congratulations, 2 valentines, 6 birthday, 6 thank you, 2 sympathy, 2 anniversary, 4 blank, 2 get well, 6 holiday, 4 new year, 2 mothers day and 2 fathers day. Never be caught without the perfect notecard!
$60.00 at Elsewares

Grow A Note® cards are embedded with seeds that can be planted to sprout wildflowers in the spring. The cards are printed with soy inks, and are handmade and tree-free.
$10.95 for 3 with a recycled content envelope at Green Field Paper

This one says: “here’s my heart”. 30% post-consumer waste and acid free.
$1.95 includes matching envelope at Girly Whirly

All cards and envelopes are made of 100% post-consumer recycled paper.
5 for $4.95, 10 for $9.75 and 50 for $44.95 at Doodle Greetings

And if you want to bag the whole holiday card ritual and send an e-card, here are several sites that can help: the Red Cross, Care, Heifer International or Accion International.
If you know other e-card sites, please leave them in the comments.
Thanks to So What Can I Do for the links in this post.

Grow-A-Note Holiday cards are truly unique and eco friendly. Only recycled post-consumer pulp and cotton is used to manufacture this amazing paper, which is then embedded with wildflower seeds. After the holidays, your card recipients can just throw the card in the ground and watch the flowers grow!! That’s the Holiday Spirit!!
$15.00 for 6 qty at KidBean

Here the designs are a bit more traditional and predictable. However it is another good place to order large quantities at goods prices. All are printed on recycled paper with soy inks and are certified by the Forest Stewardship Council. The Forest Stewardship Council (FSC) is an international network which promotes responsible management of the world’s forests. On the back of the card is printed “FSC Mixed Sources Product group from well-managed forests and recycled wood or fiber.
$42.00 for 25 qty at Hammond Greetings & Promotions LLC

Some fun designs available at Weisenbach Specialty Printing (great prices for large quantities). All are printed on recycled paper and use soy inks.
$.95 each when you purchase 100 qty at Weisenbach Specialty Printing la