This is location based but if you are in southern Cal I recommend usedgymequipment.com . They have a great selection of refurbished equipment. I’m assuming you are talking about a real gym and no a minimalist training studio.
I just purchased some refubished equipment for the Gym Store. I highly recommend them. The equipment arrived in like new condition. It was shipped very securely. And the cost saved me about $2500 dollars over the next lowest price that I could find.