Hello,

How can i see the costs per task seperated into materials costs and work costs?

Tnx

In the Task Usage view, add the Cost field.
Add the Text1 field and create a formula: [id] & " " & [Name]
Create a custom group with the following definition:
Group by:
Field: Text1
Field Type: Task
Order: Ascending
Then By:
Field: Resource Type
Field Type: Assignment (you'll need to check off the option "Group assignments not tasks"
Order: Ascending

Apply the group. Does it get you what you need?