Back at the second halving there were tons of Antminer S4/S5 that were all sold cheap. I bought a few of them to play around with the firmware. Was able to undervolt it and make it run fairly quiet. Then 6 months later or so I just sold them on Craiglist for $50 or so.

At first I though it was a waste of time because they would never turn a profit and I will get lowballs for $10 however to my surprise they all sold. To avoid headaches I even put a disclaimer saying that these are for hobby use only, they won't turn a profit because they consume more electricity than they make in BTC. People understood and they wanted to buy it anyways.

So for $50 or so, you can probably find a buyer. Just don't expect to get $300 for them.