Depends entirely on your intended use...RPi? Which model? Assuming RPi 3B+, 2.5 Amps at 5 Volts is required, especially if you plan to use USB accessories. Still, most of what was present on the web page you gave requires a higher DC voltage input...so they do not connect directly to the mains. If your need is for a mains powered RPi, there are lots from Adafruit, Sparkfun, PiHut and Amazon that are specifically built for the RPi and plug directly into a wall socket. So what are you going to do with it?