Best deal we ever see, only happens a handful of times each year
Of all the gift cards out there, an iTunes code is probably the most popular. You're offering someone instant gratification in downloadable form, and heck, it's rare to find a person who doesn't like music (or a Mac user who doesn't ever pay to upgrade their OS at some point or other).
Today you can get or give that instant gratification near-instantly.
You can get a $50 iTunes code for only $40 - a 20% discount - at Walmart today. Just pay, you get the code in your email, and you get the music, movies, software, or whatever else on the iTunes Store.