So, you can't use this on gift cards, I've already tried... but if you live in a city with same day delivery, Amazon's got a $20 off $50 promo going on their smartphone app.
I've got a pile of soda, chips, and bbq sauce coming my direction with guaranteed by 6pm delivery. Everything cheaper than shelf price at the store.
Works on other crap like video games and such.
Photo updates later...