Eh it could be great, might not be... I bought my first three mechs from Ebay; the first one was GREAT, a solid brass constructed (tubes and contacts) King clone that came with a pouch for $16. I was so happy with it that I took my chances on a black King and a SS Nemesis, wasn't so happy with either of those. The threads on the nemesis were crap (locked up on day 2 and were very thin), the entire thing was very thin and cheap feeling, and the "adjustable" center pin was too short to actually adjust and barely made contact with flat tops -- resulting in having to loosen the already wonky fire button that liked to unthread itself. The black King looks nice but doesn't hit half as hard as it's brass cousin.
But hey if you spent less than $20 then no damage done even if it sucks... You can just flip it, sit on it as a backup and buy another, or upgrade it if the center pin/switch are problematic.