There are two versions of G Suite for corporate use: G Suite Basic and G Suite Business. Comparison is to be found for example here: https://support.google.com/a/answer/6043385
Both versions are available with flexible or yearly tariff.
- Number of users is increased or decreased whenever you need. You only pay for services you have been really using each month.
- Services invoicing is monthly.
- You commit yourself to use G Suite for one year with a certain number of licenses (users). Your capability to add more users is limitless, nevertheless, after removing users followed by decrease under subscribed number of users during the year, there is no money-back.
- Using G Suite with annual tariff, the price per account is reduced, compared to flexible tariff.
- Invoicing one year in advance.
Learn more here: https://support.google.com/a/answer/1247360