Ending today at 5 pm ET, United States Postal Service via eBay offers the USPS New Civil War: 1862 Forever Self-Adhesive Stamp Souvenir Sheet for $5.88. Better yet, add 13 sheets (156 stamps total) to your cart for $76.44 and apply coupon code "C15SPRING" to cut the price to $61.44. With $1.30 for shipping, that's a savings of $31 and the lowest total price we could find. Each sheet includes 12 stamps.

Note that this coupon is usable once per PayPal account.