Look at the Non - Usage formula in here, basically I am just taking the records that are marked as non-usage (I am assuming that 'yes' means they aren't using it).
I added both the sum(cost) and the sum(non-usage) to the rows shelf and made them a dual axis graph. Make sure you sync the axis as well.
Tableau Sample.twbx 7.6 KB
Thank you! This worked! I appreciate you taking the time to show me a very simple answer to my question. Along the way you have made me more familiar with the syntax for creating a calculated field. Thanks again!