Some Ryzen chips (I think- might be TR) often support ECC- see if you can find a compatible mobo that supports ECC modules and Ryzen sand! When I last checked there were a few products out there
I've just checked and there's some mobos for $60 with ECC. Is that for real? Supermicro costs like $1000, half that for refurbished.
Without looking at the listing I can't earnestly say what you're seeing isn't fake but I know back when I had the same question you're asking here I saw similar offerings. Ultimately I bought a used ITX supermicro mobo+CPU combo unit from eBay for like $200