Fullbeauty offers the King Size Men's Big & Tall Shaker Knit V-Neck Sweater Vest in several colors (Navy Marl pictured) for $29.99. Coupon code "JLE4310" cuts it to $17.99. With $5.99 for shipping, that's $42 off list and the lowest price we could find. It comes in big and tall sizes from L to 2XL, although not in all size/color combinations.
Note: It also available in 3XL to 5XL for $19.49 plus $7.99 for shipping, or 6XL to 8XL for $20.99 plus $7.99 for shipping.