Suppose a player can construct a robot built from various parts and each part costs money. How would you balance the cost of a weapon against its capabilities? What about balancing weapons against other parts?
The base case seems pretty easy: imagine the player can only buy weapons and everything else on the robot is the same. A machine gun that fires 1 bullet per second costs $100. A super machine gun that fires twice as fast could cost twice as much. But what about an ultra machine gun that has four times the range?
Now imagine the player can add other capabilities to the robot like better speed or armor. How do you relate the cost of a machine gun against the ability to move very quickly, or to be stealthed against radar?
I understand that there's a later stage of experimentation where costs and capabilities are adjusted, but where do you start from?