And today, the Lifehacker blog published the results of a weeks-long price comparison it did between Amazon and various brick-and-mortar retail businesses, asking “Is it actually cheaper to order everything from Amazon?” and concluding that the answer is “Not always, even when the shipping costs are free.” 

But results vary based on what sort of item you’re buying, as well as what store you’re buying it from.  If you’re in the market for small appliances or electronics, Lifehacker found, Walmart is generally cheaper than Amazon, but Amazon is cheaper than Best Buy.

Lifehacker also determined that where grocery costs are concerned, Amazon is routinely more expensive than regular grocery stores. However, it’s worth noting that food costs can vary wildly depending on where you live or what time of year it is.

(Speaking for ourselves, we’ve noticed one specific subcategory of groceries where Amazon is consistently cheaper than retail stores: import items, bought in bulk. We personally are addicted to a certain British candy bar which, in America, we’ve only ever seen for sale in the expensive “British tea shops” you’ll see in touristy areas, or occasionally in the “British imports” section of certain upscale grocery stores. Compared to what such stores charge, that candy bar sells for half the price on Amazon—if you buy a dozen at a time.) 

When selling physical books, Amazon either ties or beats prices at Barnes and Noble, but for ebooks, Amazon offers no across-the-board benefits compared to its competitors: some titles sell for more, some for less, others about the same.

Here’s a good rule to follow, whether you’re shopping from Amazon or anybody else: never assume anybody automatically offers the best price on everything. A few minutes spent comparing prices now can save you a lot of money later, when you’re ready to make your purchase.