This requires that your AMEX card has the Martha Stewart Wine offer of: Spend $50 or more, get $20 back.
1) Add the AMEX offer "Spend $50 or more, get $20 back" from Martha Stewart Wine Co.
2) Go to https://marthastewartwine.com and sign-up for account membership.
3) Go to https://marthastewartwine.com/packs/patio-sippers-half-case[marthastewartwine.com] and add the item having name Patio Sippers Half-Case(6 bottle wine pack).
4) Go to Checkout, and use Promo Code: SPRING25 for 25% discount. 16.75$ discount will be reflected , making the total cart value as 50.25
5) Make sure the payment done through your AMEX card and the offer is added as mentioned in Step-1
Effectively, we are getting (50.25-20)=30.25/6= 5$ per bottle without tax plus free shipping.Seems a good deal