Trader Joe's is probably closest to what you want. It targets single shoppers with small quantities and low prices, and it rotates products frequently to keep things interesting.

Anecdotally I feel like a lot of TJ's shoppers shift into Costco shoppers as they age up.

The nice thing about Trader Joe's is that you can be in and out in 5-10 minutes if you're just buying weekly food items. The store is modestly sized and the checkout lines are short. I'm in there about once a week.

I go to Costco once every three months or so and buy paper towels, detergent, and other consumables that have long shelf lives. I don't feel drawn to it; it's just the warehouse for boring items to buy in bulk. Their hot dog is OK. But a lifestyle? No.

My wife and I shop at both Costco and TJs. They are our favorite stores...

We're a bit odd though. Highly budget conscious, 4 kidsto feed (including 2 teenagers), and European tastes in food.