I want to upgrade my Pis to something more reliable and not SD-card based and refurbished thinclients/SFF workstations seem to be a viable route. Does anyone have a cheap source for used hardware like this in Germany? I feel like the usual esm-computer, green-IT etc. are a bit overpriced.
I think you need a ton of patience, the prices for used hardware are fluctuating by a wkide margin. And all of a sudden one single machine type will be available in quantities, for cheap. Probably when a big player scraps all of their equipment.
I've had some luck with Harlander, mainly with monitors and a document scanner. Might be worth a check from time to time.