New Azure Subscription + Azure Backup Cost for 2 TB Physical Machine

Hi

I need some info relevant to Azure Backup Implementation in an Environment where there is Physical Machine Having data of 2 TB and need a Backup on Azure 

1) Which Azure Subscription is Best for this solution since i do not have any

2) What will be total cost of that 2 TB first time and if let say I backup 2 TB initially and after a MONTH become 3 TB then Azure did backup again or just new 1 TB data

Please guide its urgent.