Visual Basic Sequential Access File- Displaying dollar sign with two decimal places

Who knows how to format the numbers entered into the txtGrossPay.txt to have a dollar sign ($) with two decimal places, that also displays in the list box?

Option Explicit On
Option Strict On
Option Infer Off

Public Class frmMain

    Private Sub btnExit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExit.Click
        Me.Close()
    End Sub

    Private Sub txtGrossPay_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtGrossPay.KeyPress
        ' allows the text box to accept only numbers, the period, and the Backspace key

        If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso e.KeyChar <> "." _
            AndAlso e.KeyChar <> ControlChars.Back Then
            e.Handled = True
        End If
    End Sub

    Private Sub btnSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSave.Click
        ' saves a gross pay amount to a sequential access file




        ' declare a StreamWriter variable
        Dim outfile As IO.StreamWriter


        'open the file for append
        outfile = IO.File.AppendText("gross.txt")

        ' write the name on a seperate line in the file
        outfile.WriteLine(txtGrossPay.Text)

        ' close the file
        outfile.Close()

        ' clear the list box, then set focus
        lstContents.Items.Clear()
        txtGrossPay.Focus()
    End Sub

    Private Sub btnDisplay_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDisplay.Click
        ' reads gross pay amount from a sequential access file
        ' and displays them in the list

        ' declare variables
        Dim inFile As IO.StreamReader
        Dim strGrossPay As String

        'determine whether file exists
        If IO.File.Exists("gross.txt") Then

            ' open file for input
            inFile = IO.File.OpenText("gross.txt")

            'process loop instructions until end of file
            Do Until inFile.Peek = -1
                strGrossPay = inFile.ReadLine

                'add gross pay amount to list box
                lstContents.Items.Add(strGrossPay)



            Loop

            'close the file
            inFile.Close()
        Else
            MessageBox.Show("Can't seem to find her for you sir!")
        End If
    End Sub
End Class

Select allOpen in new window