For collaborative cost tracking, Google Sheets would be the best-suited option among the tools listed. Google Sheets allows multiple users to edit and view the same document in real-time, making it ideal for tracking costs collaboratively. Users can input data, create formulas, and share insights easily.
While Asana is excellent for project management and task tracking, it may not provide the level of detail or flexibility needed for detailed cost tracking like Google Sheets. Slack is primarily a communication tool that does not focus on cost tracking, and Toggl is designed for time tracking rather than direct cost management.