yeah, i'm not sure how subscriptions entered into the picture.
i suppose if a subscriber completes the achievement/quest they could get bonus credits, that would give more incentive to subscribe and reward current subscribers.
The easiest way would be to create a category of "free" clothing that is directly related to badge achievements.
So, for example, a mining helmet that lights up for folks with high level mining related badging.
Or, perhaps a set of overalls related to AK achievements.
Or, perhaps a welders apron for high levels of smelting.
The possibilities are rather endless.