Through Saturday, use this coupon to get a $10 gift card when you spend $50 in-store at Target. That means you can get $60 worth of stuff for $50. That amounts to a 16.67% discount.
Yes, you can buy merchant gift cards, but not Target gift cards. Some people have reported success with buying Visa gift cards. You can use Target gift cards to pay for your purchase.
RomsDeals has the details (but arguably the wrong math) here.