They're selling it

Because it doesn't work anymore

Because it doesn't turn on

Because they don't have the power cord

When people return their rented cable boxes at my office it's a 50/50 shot whether they bring in the power cord. They'll turn their roku (that didn't come through us and they're totally going to miss and want back) but they won't bring the power cord to the set top box.

Often the same people selling said power cord, separately :/