Hi @MathewB,
After we tested, we found it is difficult to convert the Currency/Money field in Dataverse to a string/number in the Cards. However, we found another way.
You can Create a new column, which Data type is Decimal and Behavior is Calculated, and Click “Save and edit”.


A pop-up window will pop up next, edit the details in here. We need to Click “Add action” and search the column which you want to convent. Then, Click ”Save and Close”.




We can see the Data Source from Dataverse has been worked.

Back to the Cards, We need to write the formula into the textLabel like this.

Click “Play” and we will see it is worked.

Above All is the method for solve the Issue. Hope that will help you.
Best Regards,
Tina