hmm... it would seem it also goes to 0 cost at any point when you have 609 energy, 1% acc, and just raise weight and attack, to cancel each others cost out, it still costs 0. hope this helps
weight: 99960
energy: 609
attack: 10036508
Acc: 1%
cost: 0
oh, and I think a side note should be put here, just because this system says it costs 0 credits, WON'T make the ship free, this will still actually cost almost exactly the same in the end. each weight you use on the system, or any system, will eventually cost you total of 165. every point of energy will eventually cost -something- while making the powercore, which then means more weight used, which then means more cost in the ship overall. so technically, while this may -appear- to be a major problem, getting a system for free, in reality, the system STILL is not free, as long as it uses ANY energy and weight.
hope that helps any reading this thinking 'WOW, I gotta try that, the perfect weapon!' because the weapon system itself won't do anything, without a ship, and that has no chance of ever costing 0.