Unit production cost increases progressively with every Barracks unit on the field or currently in production. The default increase is of 1 File:Food.jpg Food and 1 File:Metal.jpg Metal for the second unit created, and grows exponentially from then on. Upgrading this unit costs double the base cost of the unit it will upgrade to; this means that the upgrade to Phalanx has a cost of 100 File:Food.jpg Food, 60 File:Metal.jpg Metal. It's important to note, however, that these prices are the default standard, and actual production and upgrading costs may differ, depending on researched technologies/ages, connected rare resources, or adopted governments.