This window displays the costs of each player's fleet. Because not all costs are spent for just this one battle, you can use the options dialog to configure what to include. You need at least one ship in the simulation to access this dialog. The overview always includes the costs for building the actual ships and their weapons.

Reference

Keys:
CtrlC from battle simulator
This is a testing version.
It may be incomplete, and have more bugs (or features) than the public live version at planetscentral.com.