In Simplify360, most of the time you would be creating new keyword profiles, adding channels and users. Hence it will be very difficult for you to keep track of all your resources. Hence if you want to see how much VOLUME is remaining and how many new channels or profiles you can create, Click on ADMIN> PACKAGING.
You can view the status of your packages and drill down to details of all the resources, which are being used up.
Note that in the Profile Volume, Used Amount means total allocated Volume and not used amount.