I work at a store that does $300k a week. The actual size of the store and volume of customers seems about average. There are 10 checklanes including sco, a fuel center. The store serves a mostly working class population so that while there is a pretty good volume of customers, the dollar amount per order is lower (kroger brands and p$$t brands often get significantly larger allocations of shelf space because they sell better than brand products). What's considered small, medium and large?
I'm at a store now that does less than 300k a week now, has 13 aisles and no sco, fuel center, or pharmacy. That's a small store.
My home store does about 700k-800k a week and I would consider that an average store. It has over 20 aisles and has a fuel center, pharmacy, and all service counters.
I would consider a large store one that does more than a million a week in sales.
The store I work at does about 1.5 M a week in sales. It's not a Marketplace store but it's nearly the size of one (109,000 sq. ft.) It has 32 aisles not counting the bakery and deli section. They probably take up the equivalent of 4 or 5 additional aisles. I know it has two sets of U-Scan lanes with 6 bots each but I'm not sure how many regular lanes it has.