As someone who shops very cheaply for groceries, I can attest that low-end prices have risen signficantly over the last 3 years or so. Used to be you could find chicken legs for 49 cents a pound at times, now the cheapest you see are 79 cents. Potatoes? Used to be able to commonly find them for 99 cents for a five-pound bag, the last time I saw them at the price the spuds were very poor quality. Fair quality spuds are 1.49 a bag cheapest now. Store-brand tub margarine? Gone from 1.99 to 2.99.
Other examples abound. Those are significant percentage increases for someone on a very tight food budget.
And this is why a lot of people question the official inflation stats - their own eyes are telling them something very different.