It depends on what you buy but in general, the manufacturer's website will often cost more than Amazon. E.g. In the USA, Apple Watch 46mm GPS+Cellular is currently $429 on amazon.com but $529 on apple.com
Also, manufacturers are often contractually required to have higher prices (i.e. MSRP) than the retailers that sell their products. So getting a discount from Amazon is more realistic than the manufacturer's official website. Another example is buying TurboTax software on Amazon ($55.99) costs less than Intuit's website ($80)
>Third, Amazon’s prices aren’t notably cheaper than the alternatives.
Again, it depends on what types of products you're buying. For things like USB cables and rechargeable batteries, Amazon costs less than Best Buy. Buying a Fiskars garden shears cost $10 less at Amazon than Home Depot and Lowe's. What's happening is that those local stores are using price discrimination to upcharge the impatient walk-in customers who need "instant gratification". Home Depot charges $5 more for a toilet plumbing repair kit than Amazon because they know customers are likely making an emergency purchase. Yes, the local stores sometimes have a "match Amazon's price" policy but it's a hassle to hunt down a manager and get an override of the price at the cash register.
Where Amazon often costs more (often 2x because of shipping) is commodity household items like toothpaste and Windex glass cleaner. A local Walmart will have cheaper prices on those.
Lastly, I recently went through my 200+ accounts in my password manager to migrate my email address and the lesson I've learned is to avoid creating new accounts at more ecommerce websites. It's not worth it. Maybe I'll make an exception for Shopify in the future because a lot of sellers have consolidated there but I'm going to hold out as long as I can.
I really like having my orders history in one website instead of scattered across Newegg, ZipZoomFly, BHPhotoVideo, etc, etc.
[1] https://www.amazon.com/Apple-Cellular-Smartwatch-Aluminium-A...