As one of its daily deals, 13deals offers this 6-oz. Stainless Steel Flask for free. Coupon code "DN-13FLASK" cuts shipping to $2.99. That's $1 under our mention of an 8-oz. flask and the lowest total price we could find for a 6-oz. flask by $3. This stainless steel flask measures 5.4" and features a screw cap. Deal ends April 31.