There are a few ways to collect resources. The first is upgrading your oil refineries and farms so that they produce more. The second is to gather oil and food with your army on the map. The third is to complete the daily quests and receive the resource rewards. If you’re trying to save up for big upgrades then just try to save the resources and not spend it on a lot of troops or expensive buildings. Buy just the bare minimum of troops needed to receive the daily quest rewards, and upgrade one cheap building per day while you save up for the upgrade. Hope this helps.
Are you referring to the power ore with which I started the Infinite Zombies game? I got +1200 power ore from the purple armament I selected before the game started when I chose which armaments to use. You can buy different armaments with gold in the Armaments tab when you open Infinite Zombies. And you can collect gold in different ways while playing the game. You don’t need to spend any real money. Personally I haven’t spent any real money on the game.
