Thank You Susan for your information because it was very helpful. I was able to finally cancel the Jillian Michael's app. It's funny how easy it is to add an app from your iphone but you literally have to go to your computer to itunes under store, view my account and sign in then scroll down to setting and manage your subscriptions. Now thanks to you I have successfully deleted the Jillian Michael's app that I did not sign up for the subscription of $3.99 a week. It's a free app when downloaded on your phone but it is obviously not free.
In the latest version of iTunes (12.1), you go to Store, and, from the home page, click on "Account" on the far right near under "MUSIC QUICK LINKS." On the next page, find the "Settings" header, and, in that list, you'll see "Subscriptions" in the left column. Click the corresponding "Manage" in the right column, and you can take it from there.