Do not need default selling price & need 0.00 /Not assigned price

Hi all,

I am trying to customizing the shopping cart module.
I have some products for a specific pricelist. And I want to show the price for this pricelist for the items.
But some of the products in my warehouse have no price assigned in ‘Item price’ for the specific pricelist. So it shows the price of the previous product’s.

I want to show, if no price is added for the specific Price list, it must show rate as “0.00” or ‘No Price is assigned’

Can anybody tell me how to solve this issue?