I only accept Paypal Payment !!! ( Other payment, exp. Any Cheque ,Any Money Order, Bank transfer,..... ! ), I NOT accept 
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Please refer below about Combine shipment details :

Under 3pcs products, I still charge Each item Original Shipment charge ( Not discount  )
Over 4pcs - 6pcs products, Each item shipment charge Less 10% discount 
Over 7pcs - 10pcs products, Each item shipment charge Less 15% discount