Right now you can go to American Greetings and print off a $2/2 coupon (not valid on cards less than $1). This covers American Greetings, Carlton Cards or Just For You.
Also, Target has a coupon available on their site for $1/3 cards (also not valid on cards less than $1). Here's the deal:
Buy 4 Cards at $1.29 (there have a selection, but you'll need to look. I usually find them close to the $0.99 ones). Total $5.16
Use 2 $2/2 coupons. -$4
Use 1 $1/3 coupon.-$1.
Final Price: $0.16 for all 4 or $0.04 each.
For those wondering about buying 6, the Target coupon says 1 coupon per transaction. Some stores will overlook this (mine won't usually...). If they let you use 2 $1/3, then combine 3 $2/2 & 2 $1/3. Final Price with the $1.29 cards will be a $0.26 Moneymaker!