Apart from the fact that it is the wrong board to post it here,
I don't think that it is a good idea to buy a second- handed miner. It is better for someone to buy it directly from bitmain. Also, it is a little bit old miner as there are a lot of machines with better hashrate right now.
You must be joking. Most S9s sold today are used, because they are old, and they cost like 100 USD, when they used to cost 3000 USD some 3+ years ago.
Also the remainder S9s sold by Bitmain are of low quality yields, the s9e appears to be the worst of them. The i is good and the j is the best, but you are not getting those new anymore.
Those of us with very cheap (or free) electricity are potential buyers. It is true that the S17 is much more efficient, but its also way more expensive, and the goal for any buyer is to lower their ROI, which when electricity happens to be super cheap, can actually mean the S9 pays itself faster than the S17.
Of course this won't last forever and eventually all the old S9s will be gone. And with they announcing 5nm miners, eventually the S17 too will become obsolete (and by then it might get an attractive price).
Second hand market is vital for a miner segment out there. One's garbage is somebody else's treasure...
