Your account will be charged only for setting a task.
The cost can be calculated on the Pricing page.
Setting Google Dataset Info Tasks
Google Dataset Info API provides detailed information about the dataset you specify in the POST request. You will get data from a page of the dataset displayed separately from the SERP. It contains information about dataset content, authors, licenses, and description on the SERP.
There are two different priorities that stand for the relative speed of task execution: normal and high.