how to calculate total of selected combo box items

If Me.cbobraketype.SelectedItem = ("Rim Brakes") Then
        braketype = ("Rim Brakes")
        price = "120"
        braketype = ("Rim Brakes")


    ElseIf Me.cbobraketype.SelectedItem = ("Disk Brakes") Then
        braketype = ("Disk Brakes")
        price = "150"
        braketype = ("Disk Brakes")



    End If

    'choose type of frame
    If Me.cboframetype.SelectedItem = ("Aluminium") Then
        frametype = ("Aluminium")

    End If

    'choose type of brakes
    If Me.cbobraketype.SelectedItem = ("Rim Brakes") Then
        braketype = ("Rim Brakes")
        price = "390"
        braketype = ("Rim Brakes")

    ElseIf Me.cbobraketype.SelectedItem = ("Disk Brakes") Then
        braketype = ("Disk Brakes")
        price = "430"
        braketype = ("Disk Brakes")

    End If