Looks interesting, both the laser and power supply in a neat package. That gas cylinder may indicate it's a flowing gas laser though, see if you can check that. Usually only high power lasers are flowing gas, so it may just be for something else.
And there's always the chance is just broken, which may or may nog be easily fixable. But for the price I'd take a chance. If looking at the laser beforehand is possible that would help a lot.