It's been a while since I first took a look at Adrenaline Monki's Mooniz, but I remember spending what could be considered way too much time with it. As I've said previously, it's a battery eater. Since then there have been some updates including better compatibility with older devices, making it accessible to an even larger audience. Well now it's about as accessible as it's going to get, because Mooniz is completely free for a limited time.
That's right, for the low low cost of absolutely nothing, anyone can use their iOS device to save the world from an invasion of super-cute and cuddly lunar critters. As before, there are still in-app purchases for coins that can be used to buy power-ups, but none of that is really necessary in order to have a good time with it. Keep in mind, this "limited time" deal doesn't have any discernible end date, so I'd suggest getting a move on if poking colored moon monsters in the name of population control sounds like a thing worth doing.