@kitten For ESP32 and LEDs and cables and connectors and things like that, AliExpress is good! And for more specialized parts we've had success with DigiKey. Because searching for specific items is very hard with AliExpress
@kitten amazon tends to be way more expensive than AliExpress. Problem is that most boards have the lowest flash configuration, so if you need for example 8MB or 16MB you would probably need to buy the modules themselves. Also none of the Ethernet dev boards have USB (but I'm planning on fixing that soonâ„¢)