Subscriptions are managed by your respective app store in your device settings, not in the SOPr app.
For Apple users. Settings > Apple Account > Subscriptions > SOPr
Yes, if you select the annual subscription you will start off with the first week free, be sure to cancel your subscription before the weeks up if you don't want to continue.
Go into settings, and select the equipment you'd liked to share, enter the email of the person you wish to share it with. (Note: they must have an active subscription to view it)
*sharing is view only, the other user(s) cannot edit it