Azure ML Studio pricing and how to shutdown when not in use

HI All,

I am new to Azure. I started learning azure machine learning recently, using Azure ML Studio (classic) coz I read that it is a free service. I just tried a small experiment in it, few days back and logged in today after that , just to try some more stuff. However , after logging in , I checked the cost management section and saw that ML studio had incurred some costs for each of the past few days, even on the days when I did not login.
so, couple of questions here -

1) isn't ml studio (classic) supposed to be free. If so, can someone please explain why the cost being displayed on the cost management page?

2) based on some other faq's , which were not specific to the classic version of ml studio, but just ml studio in general - I got to know that if the resource which is running the experiment is not shut down, it will continue to incur daily costs. so, even in the case if ml studio is not free- can someone please tell how we can shut down the compute instance associated with ml studio? I could not see any such compute instance in my resources on azure home page.