The following are ways on how to format string number values into a money format with decimals.

Option 1: - Using String.Format method

C#

double formatToMoney;
string num = "1500";
if (double.TryParse(num, out formatToMoney))
{
            string newNum = String.Format("{0:c}", formatToMoney);
            Response.Write(newNum);
}

VB.NET

Dim formatToMoney As Double
Dim num As String = "1500"
If Double.TryParse(num, formatToMoney) Then
    Dim newNum As String = String.Format("{0:c}", formatToMoney)
    Response.Write(newNum)
End If

Option 2: using .ToString() method

C#

double formatToMoney;
string num = "1500";
if (double.TryParse(num, out formatToMoney))
{
            string newNum = formatToMoney.ToString("$#,###.00");
            Response.Write(newNum);
}

VB.NET

Dim formatToMoney As Double
Dim num As String = "1500"
If Double.TryParse(num, formatToMoney) Then
    Dim newNum As String = formatToMoney.ToString("$#,###.00")
    Response.Write(newNum)
End If

That's it! Happy Coding!