Hi Simran,
Welcome to the Elastic community! 
Is the cost of running fixed for each user? Is this information present in the document?
There could be possibly two ways to solve it, and it depends on what you want to do with the data.
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Use Elasticsearch SQL
How to multiply two columns and then sum the result in ElasticSQL?
The PR for this is merged already.
This is especially useful if you wish to use canvas and showcase your data. -
Scripted fields in Kibana
A simpler way if the cost of each entity is fixed and not changing. But you could end up having to create multiple visualizations if the cost is different for each user.
https://stackoverflow.com/questions/50403676/add-math-to-metrics-in-kibana