How to Format Databound label to Currency with ZERO decimal places?

                            <asp:Label ID="RentCostLabel" runat="server"                                  Text='<%# Bind("RentCost", "{0:C}") %>' />Just trying to display a currency value with no (zero) decimal places but can't find it anywhere, for some reason nobody wants to do it. 
Currently I have this which formats to 2 dp.
                            <asp:Label ID="RentCostLabel" ...