Centipedes use to sell in my neck of the woods for a solid $500-$700 a couple years ago. $500 seems to be top range these days, I'd say as low as $350 for a 6/10 working cab.
Damn you arcade market!
The game is worth it if you get it for a price you're happy with and you enjoy it. Completely up to you. I'd like to own one, but only if I landed it for a smoking price, and only if it had great sideart.
Watch for water damage down low. They're old machines, they were produced in great numbers, and it seems most of them I've seen have been around the block on swelling.