Bubbling Hearts $15.00 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: 724. Category: Hearts. Related Products I Love You from the Bottom of My Heart $15.00 I Only Have Irises for You $15.00 All I See Is You $15.00 My Heart Bleats $15.00