Call of mini zombies mod APK is a free to play game but you can get relaxed on some aspects by having some in-game resources which are available for purchase via real-life money, if your device is rooted then there's nothing to pay for this game because mods will do all the work for you.
There are two modes to play in this game apart from the campaign mode which is single and other is multiplayer and the third one is zombie mania where you will survive on a small island, fight off zombies and complete your objective by collecting items.