is anybody interested in doing this?
Coupon trains are simply a way of exchanging coupons via postal mail. This means those “Great Coupons” that aren’t available in your local paper, supermarket, or even mail just may be in someone else’s. That pile of “free” products or coupons you were going to discard may be exactly what someone else is looking for.
check this out for more info: http://www.grocerycouponguide.com/articles/introduction-to-coupon-trains/