Hey!
I can answer this pretty well as I grew up and lived in a pretty car dependant Minneapolis until I was 23, where then I moved to NYC with no car in 2018 and have lived here ever since.
The TL;DR to this question is that you transport everything in a grocery bag on person, but the longer answer is that your buying and cooking behavior changes.
Back in Minneapolis I relied on buying in bulk, since I wanted to limit the number of trips in the 15-20 min drive between my apt and the Costco. Variability with the weather affected this too, as I would buy extra if it was in the winter time. I’d make this trip by car around 2-3 times a month. This also affected my buying and cooking decision making as well. Buying groceries first then figuring out what I wanted to cook.
Once I moved to NYC, I would always have a grocery store several blocks away from me. At most being a short 5-10 min walk. This changed my habits as I always had a grocery store I could quickly pop in without having to think about traffic, my car, etc. So although I would go more frequently (~ 2 times a week), I would also find this a lot easier and would buy less.
Nowadays, whenever I think of wanting to cook something, I either head over to the store on my way back to the office, after the gym, etc. and then cook that very same day what I bought.
In my mind, that big fridge I used to restock with my Costco runs has been replaced by having that quick grocery store within walking distance.
Purely anecdotal, since I know some other people in the US may be living different than a single guy living in an apt in NYC, but this is also how it is in many cities I’ve traveled to in Asia and Europe.
Hmm on my end the answer is tough because it really matters haha
In Minneapolis I was exclusively going to Costco and Cub Foods. Costco, things were cheap in bulk, while Cub Foods you always had good deals in coupons.
Estimated bill from Costco being 80-100 every 2 weeks, Cub probably 60-70 every 2 weeks (this is in 2017, so pricing has changed quite a bit haha)
In NY, my bill shifted based on where I shopped.
When I lived in midtown Manhattan on 54th and 7th in 2018, I went to the Whole Foods in Columbus Circle and would leave with a bill around $60 a week. But back then when I first moved, I was also eating out a ton.
Nowadays, I live in LIC in Queens and go to some local grocery chains and cook a whole lot more. My weekly spend is around $120 or so a week. But I’m also cooking a whole lot more than I used to and eating out a lot less.
I forgot who said it, but someone said it best “if it weren’t for rent, NY would actually be very livable cost-wise.”