Save on shipping with multiple orders!    
Buy 1 Litter Box - Shipping is $16.00 per box.    
Buy 2 Litter Boxes - Shipping is $8.50 per box.    
Buy 3 Litter Boxes - Shipping is $6.00 per box.    
Buy 4 Litter Boxes - Shipping is $5.00 per box.    
Buy 5 Litter Boxes - Shipping is only $4.40 per box.

There is a maximum of 5 litter boxes per shipment, so quantities above 5 will constitute

two shipments, increasing the shipping costs relative to the added number of boxes ordered.