Amazon has a metric boatload of Zigbee smart outlets, see the link below as an example. They don’t specifically show up as compatible devices in the big list. I suppose they could be branded differently like all the aqara stuff shows up as Xiaomi.
How do they work with Zigbee2mqtt?
Does it work fairly seamlessly or is there a bunch of manual setup?
The real point is though, they will probably work, or at least possibly work, or will work with writing a bit of code. But there are two supported devices list, so why not buy one off the lists?
Really it is the price. The two from the Zigbee2mqtt devices list I can find on Amazon are the Sonoff and the Aqara. They are double and quadruple the price respectively. It looks like if the device is not I need a herdsman converter.
You often buy these things and they are equal to some supported device, just look at the identical looking devices. Buy one and try it. As you say, cheap.
If it does not work then the next step is to search to see if can find if someone else has already placed a “New device support request” for it and if not then place your own “New device support request”: