Since my assignment here is for more than 30 days, my food allowance is reduced and the place where I live has a kitchen, so that I can do a little cooking, which means I get to learn how to navigate through grocery stores in a foreign country.
Overall, they work about the same as in the States, with a few exceptions. Just as we have a variety of stores catering to different budgets, there are about 5 different grocery store chains here, ranging from the budget Shoprite to the luxury Woolworths (named after the defunct American chain, but was never related).
I've shopped in 4 of the chains, and because the store sizes are usually quite a bit smaller than American stores, and the hours are much shorter, I usually end up in 2 different stores during the course of the week. The latest any grocery store near me stays open is 8pm, but most close earlier. The food here also seems to have a lot fewer preservatives, so "use by" dates are often just a few days away.
There are a few hypermarkets, which is a word known in most countries except the US. Super Target and Super Walmart are examples of hypermarkets, but we just don't use the term. The Checkers Hyper that is near me is probably 3/4 the size of a Super Walmart, with a similar mix of groceries and household items, although curiously it closes at 6pm.
All but the smallest grocery stores tend to have salad bars, bakeries, a butcher, and often a hot pie stand...these would be British pies, similar (but better) than a pot pie, filled with various combinations of steak, chicken, kidney and/or lamb, all baked in a very flaky crust.
Layout of the stores are similar, with shopping carts and aisles and plenty of checkout lines. There are no free bags here; you'll pay around 7 cents US for a plastic bag, but most people remember to bring them back, or use the reusable canvas bags that have started to pop up in America.
Overall, I think prices of most goods are actually on par with the prices at home for individual items, although the bulk discounts we get in the US don't really happen here. Package sizes tend to be smaller here, and buying a 6-pack of Coke is about the same price as buying 6 individual cans of Coke.
There are a few products that are definitely more expensive, like imported American products, for the most part (Pop Tarts for $7 a box), but with the increasing globalization of many brands, there are plenty of American products that are manufactured locally at a fair price. A 2 liter bottle of South African-bottled Coke is just about $1.65, and there are quite a few flavors of Doritos available.
I'll post again soon about the actual food that is found in the grocery store; there are some interesting products in the South African market that we don't have that have been fun to taste.