My brother has extreme allergies. Growing up, goat's milk was all he could tolerate. It was expensive and was available at just one dairy and only came in quarts. I remember my dad making many trips there, just to get my brother's milk. Perhaps he threw the receipts away too, so he didn't have to think about how much it cost. With six kids to feed, it was hard on the family's budget. Perhaps this guy's kid has allergies like my brother did and he was/is committed to buying what's best for his kid's needs, despite the cost. What you see isn't always the whole story.
That said, here's my Sprouts tale and tip: Our new house is about 1.5 miles from Sprouts, which happens to be the nearest grocery of any kind. I grab the dogs, my backpack and my MIL who has Alzheimer's and we all walk there and back. (Sorry, can't trust her on a bicycle, so it's shank's mare for us. She waits outside with the dogs while I shop and they keep her from wandering off.) I make sure to do our Sprouts shopping trek on Wednesdays, when you can "double up" by buying from both the current and past week's circulars. All I buy there is the produce, but boy, do they have some great deals! Much as I love Costco, Sprouts often has better produce for far less. So, if you're going to go shop at Sprouts, Wednesday's the day.