The free 7-day trial does not cost anything and is completely free for seven days. It will give you access to all War Machines Premium perks. It is required to register a valid credit card on your app store account for the trial subscription and it will become a paid weekly subscription if you do not cancel your trials subscription a t least 24 hours before the end of the free trial.
If you want to try the free trial, please click on the free trial ad. Then, allow yourself to subscribe and remember to cancel the trial if you do not desire it to become a paid weekly subscription.
If you have already used a Free Trial in the past, it will not be possible to use it again. If you acquire a new Free Trial, a message will state that you have already used it once, and you will subscribe to a Weekly subscription instead. Also, if you try to acquire the Free Trial for a second time, you will be charged for it.