Comment by kuschku

Then check out the Serverbörse https://www.hetzner.com/de/sb/ that's exactly what you're asking for. Used servers, some of them with Skylake (2015) processors, some even with Haswell (2014) processors.

Hetzner keeps running the old machines as long as they can find customers for them, which means they have entire buildings of 10+ year old machines still running.