I do use Amazon (as well as pretty much all the alternatives listed above (plus say Ikea are great for lights and dimmer switches etc) but notice that prices are rarely the cheapest and the way they rank things is somewhat opaque. If you know exactly what you want you can usually find it elsewhere cheaper. Who here’s bought a bike from Amazon?
But Amazon are really really easy to buy from – click and that’s it and get it next day. Contrast with say Decathlon where you can fail repeatedly at the last hurdle because something’s not in stock for apparently random reasons. Or Gearbest – great for a punt, but then put it out of your mind for a few weeks as it cruises from China…