Please be advised that you won’t be charged for anything if you subscribe to the free trial (7 days). If you see a charge in your account, it can be a preauthorization charge.
A preauthorization charge is a temporary hold on a specific amount of the available balance on a credit or debit card. This charge checks that the card is valid and has sufficient funds to cover the transaction. The amount is set aside by the card issuer but not actually transferred to the business.