Groupon offers the Hawke & Co. Men's Packable Down Vest in Steel Grey for $24.97. Coupon code "SALE3" drops it to $22.47. With $3.99 for shipping, that's the lowest total price we could find by $18, excluding the below mention. It's available in size XL only.
A close price: FastShipClothing via eBay offers it for $26.94 with free shipping in Black. It's available in size XXL.