Your collaborator does not need a paid subscription; however, they will need to create a free Lato account. This way, they can edit the trip as a collaborator. They will need a subscription to create their own trips.
What Happens When You Invite Someone to Collaborate on a Trip?
You send an invitation
They sign up for a free Lato account
They can start working - Once logged in, they can view and edit the trip based on the permissions you've given them
What Does Your Collaborator Get?
With a free account, your collaborator can:
View the trip details you've shared
Edit specific fields (depending on your settings)
Add comments and suggestions
Access the trip from any device