By Default Microsoft Gives you 1TB of Sharepoint Storage ( 1 TB plus 10 GB per license purchased ) in Office 365

Recently going through a Microsoft where a customer needed more , and to my surprise , if you contact Microsoft Support, they will increase this Storage from 1TB to 3TB for Free for a Year , and you can possibly try and give them a call next the following year and see if they can redo for another year.