Hi Jiten,
The logic I mentioned is for specific country only.
Well let me clarify.
1. Enhance the WD Object
2. Create a new variable in CONTEXT with type as WDUI_VISIBILITY default as 02 [Visible].
3. Bind this value to the Visible property of your estimated cost Field as well as label.
4. Now in the Hook method WDDOMODIFYVIEW check the country and set 01[Invisible] as the value of the variable wherever required.
Let me know if you need further input.