Yes, of course, you can unsubscribe anytime you want! If you unsubscribe not later than 24 hours before your Free Trial expires, you won't be charged. If you unsubscribe anytime later, you won't be charged any further after your cancelation date. You can subscribe and unsubscribe as many times as you want.
If you'd like to cancel your subscription please follow these steps:
In iOS STRETCHIT version 2.1.1 and up, please tap Home on the bottom menu, then your Profile Picture on the top left corner, then Subscriptions and Manage in iTunes.
In iOS STRETCHIT version 2.0.12 and below, please tap Profile in the Main Menu, then your Profile Picture on the top left corner, then Subscriptions and Manage in iTunes.
You will still have access to the classes till the end of your trial period or the month (or year) you paid for.