Converting Currency Format

Private Sub Worksheet_Change(ByVal Target As Range)
    If Intersect(Target, Me.Range("A2:A50")) Is Nothing Then Exit Sub
    On Error GoTo endit
    Application.EnableEvents = False
    With Target.Offset(, 1)
        Select Case Target.Value
        Case "USD"
                .NumberFormat = "$#,##0.00"
            Case "GBP"
                .NumberFormat = "£#,##0.00"
            Case "EUR"
                .NumberFormat = "€#,##0.00"
            Case "AUD"
                .NumberFormat = "$#,##0.00"
        End Select
    End With
endit:
    Application.EnableEvents = True
End Sub

Maybe adjust that second line to dynamically target to last row:

If Intersect(Target, Me.Range("A2", Me.Range("a" & Rows.Count).End(xlUp))) Is Nothing Then Exit Sub

Private Sub KittenExposion()
Dim cell as Range
For each cell in Range("A2:A50")
   Select Case cell.Value
        Case "USD"
                Cell.Offset(,1).NumberFormat = "$#,##0.00"
            Case "GBP"
                Cell.Offset(,1).NumberFormat = "£#,##0.00"
            Case "EUR"
                Cell.Offset(,1).NumberFormat = "€#,##0.00"
            Case "AUD"
                Cell.Offset(,1).NumberFormat = "$#,##0.00"
   End Select
Next Cell
End Sub