You more or less got it, but their generics are as good as national brands(Kraft, Hormel, Green Giant...). The selection is very small. They have what you need, but not a lot of choice. It's setup like a warehouse where goods are left in boxes, and stacked. To carry groceries, you can use a box free(my preference, they're good for recyclables), or bring/buy bags. To use a shopping cart you unlock it with a quarter, and you get the quarter back when you dock it. That keeps asshats from leaving carts out, and prevents damage. They utilize every method of cutting costs, and that gets passed to the consumer. It's not an elegant shopping experience, but you can save a ton of money. You probably won't get everything you want there, but combining a trip with a regular grocer will leave you more cash.
Btw, they sometimes get special purchase items of either premium American foods, or European imports. All excellent quality, and great prices. It's German owned I believe.