Here is a Staples ink moneymaker per a reader:
"At Staples this week the flyer reads spend $75+ on an HP ink cartridge, get a free $15 Starbucks or $15 ITunes gift card. However, in store, you only have to buy 1 to get this deal. But it still gets better. You can buy the cheapest HP cartridge ($11.99), use the 20% on any item coupon and still get the free giftcard. OOP $10.36 including NY tax, and I got 1 HP ink cartridge and free $15 starbucks gift card. $4.64 MM."
This may be a glitch as flyer reads spend $75+ or staples may have just changed the deal (or sometimes they have these "gliches" for publicity) so YMMV, you could always return the cartridge on the spot if you do not receive the gift card. This deal is also reportedly working for others.