Best place to use mastery points before you can afford the good ones?
I'm a free player with the basic set up and nowhere near enough units to spend on carbo cores for the high end masteries. I have some mastery points chucked in useless places just to get rid of the notification and I was wondering which cheap masteries are best to chuck them into until I save up for the expensive ones. Also, is it worth focusing on saving up for the expensive masteries as a free player or am I better off forgetting about them and buying revives to get through content?