Working My Tail Off $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". Working My Tail Off quantity Add to cart SKU: 272. Category: Humor. Related Products Acute Pain $20.00 I Snitch the Best $20.00 Celebrate Something Every Day $20.00 You Win Some, You Juice Some $20.00