Need to create paid account in order to edit client's site

Hi there
I am a developer working with a client for about two years now. He just asked for my help in order to add some custom code in webflow. He upgraded to Teams and invited me. Webflow does not allow me to be a part of the team unless I have a paying account as well?
I never intend to use webflow apart from this instance. Is there no other way apart from sharing credentials?
Thank you

Here is my site Read-Only: LINK
([how to share your site Read-Only link][2])

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