If it's in mint working condition, that's a deal. If it's got the funky kind of mysterious little buzzes and errant static oddball blips these things develop over time... maybe no so much, but even then, someone could repair it, potentially.
"The E300S is a revised version of CAD’s E300 microphone. The new version is intended to sound the same as the E300(2).
The E300S has the same capsule and circuit design as the older version of the microphone. Like the earlier version, it uses a pair of 9V nickel metal hydride batteries to power the circuit; phantom power, when available, is used to recharge the batteries."