You could make teams and assign different credit cards to each team. Or assign credits to each team.
You would however need the credit card information for both teams.

Hello, @georgeargyrakis

As per @ForYourIT suggestion you can setup a team and have differnt payment information on the different droplets.

Teams are useful for project leaders and business owners who want to share control of server infrastructure with developers, financial administrators, and other collaborators.

You can create multiple teams and there is no limit to the number of members a team can have. Each team is billed separately and has its own payment information.

You can find more information here: https://www.digitalocean.com/docs/accounts/teams/

Regards,
Alex