Apparently $20.00 Inside Message Inside: A Parent 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: 20. Categories: Baby - Parenting, Women. Related Products Make time to play $20.00 Flowers Chase the Blues $20.00 Sing Me a Song $20.00 Speak Love, Sing Faith $20.00