Acute Pain $20.00 Inside Message Blank Inside Packages of Heartstrings® cards are shrink-wrapped and sold in sets of 10 cards with envelopes. The actual card size is 4 1/4" x 5 1/2". Quantity Add to cart SKU: 59. Categories: Baby - Parenting, Humor, Women. Related Products You Have Learned to Make Friends $20.00 Just a Little Mistake $20.00 Mind over motor $20.00 High Hopes $20.00