Probably stating the obvious here but prices can vary greatly depending on the store. I was single for many decades but now my wife does the shopping and hits a variety of stores (Sams, Costco, Winco, Safeway, Frys, Walmart) depending on the week or need. She was showing me the price for this one brand of salad dressing and it ranged from $2.50 to $6 depending on the store.

When I was a single guy my biggest things was mostly to stay in the 15 item or less line and if I saw something that I used that was on sale, I would stock up on it, but the thought of going to a number of stores wasn't in my plans.

I've never been to Aldi's although we have one fairly close but the last time I was out, it didn't open until after some of the other stores.