If cb1.text = "Web Developer" Then
l1.text = "5000 pesos"

OR

If cb1.text = "CEO" Then
l1.text = "10000 pesos"

And so forth...

Public Class AddForm
Dim qry As String
Dim con As New MySqlConnection
Dim cmd As New MySqlCommand
Dim dr As MySqlDataReader
Dim ds As New DataSet
Dim da As New MySqlDataAdapter

Private Sub AddForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Try
        con = New MySqlConnection("server=localhost;username=root;password=;Persist Security Info=False;database=pms;")
        qry = "SELECT * FROM designations ORDER By design_id ASC"
        cmd = New MySqlCommand(qry, con)
        con.Open()
        dr = cmd.ExecuteReader

    While dr.Read
        cb1.Items.Add(dr.Item(1))

        If cb1.SelectedValue Then
            Dim money As String = dr.GetValue(2)
            l1.Text = "₱ " & money & ".00"
        End If
    End While

        dr.Close()
        con.Close()
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    Finally
        con.Dispose()
    End Try
End Sub
End Class