Buy 2 pens and get 5% (£36.48) additional discount
Buy 3 pens and get 6% (£72.78) additional discount
Buy 4 pens and get 7% (£117.36) additional discount
Buy 5 pens and get 8% (£169.87) additional discount
Buy 6 pens and get 10% (£226.84) additional discount