If you’re in the “iTunes universe” - yes, I know, Apple is expensive and one should just buy the cheapest, nastiest Android tablet - and you tend to buy either content or apps there regularly, Costco currently has their $10 off deal for the $100 iTunes gift cards going in the US. Looks like the deal expires on the 16th so if you need to make use of it, do it soon.
Basically that’s a $15 overall discount on the cards, so if you’re already paying for things via iTunes, it’s a decent deal. I subscribe to several European magazines via iTunes and that’s how I usually pay for my subscriptions. The electronic (as opposed to hardcopy) subscriptions already save a fair amount of money as the shipping costs for magazines from Europe are prohibitively expensive and saving another 15% on top of it is just the icing on the cake.
It’s also just about the only time when I’d recommend purchasing any type of gift card.