Not only do I always get a really good deal and earn rewards when I buy HP ink at Staples they also honor the HP performance guarantee. I tried to save some money and bought some HP ink from an unknown vendor on a popular online site but the cartridges only printed a fraction of the pages they were supposed to. Then the vendor said there was nothing they could do. Buying from Staples is definitely the best value. Plus the cartridges last a LONG time.