The X1000 Metal storage, when placed into the VAB has a negative value of 9,360 credits, the value of the ore when full makes the module cost zero. This leads to a credit exploit where the player can make a huge stack of them (I made one for 800k) launch it to it's destruction, and then gain credits from the launch.

Of coarse if a part is recovered, the negative value is undone reducing the credits gained from the launch.

The version of the game I am using is 1.4.2 through ckan.

will make a fix for that in the update for KSP 1.3

Fixed by 17b7a20