Google One is a subscription service to "Google".
When you open a Google Account you get 15 GB of free storage which you can use in Google Drive, Gmail, Google Photos etc. Now it is not possible for you to determine how much your phone or computer is using 15 GB storage Google Drive, Gmail , Google Photos.
In that case, you can easily use the 'Google One' application to understand which of your apps have been flooded with extra space and so you can clean it immediately. After opening a Google account you will get 15 GB completely free. Using more storage, you have to pay 100 GB (1800 Bangladeshi Taka) per year or. 19.99 per month. You have to pay 99 dollars (180 rupees in Bangladeshi rupees).