from SC web
here
Discounts at vPOST*
$20 Off First Shipment (for the first 100 new vPOST customers every month)
15% Off Subsequent Shipments
50% Off Repacking Service Fee
Shipment discounts are valid only for USA, Europe, Japan shipments.
Discounts at SingPost*
15% off Speedpost EMS (Package) Published Rates
5% off SmartPac (minimum 3 pieces)
25% off Self Storage Solutions
10% off Thematic MyStamp collections and Premium Gifts
Speedpost discount not valid for payment of SaverPac Prepaid rates, EMS SaverBox rates, and fuel surcharges. Self Storage Solutions discount is only applicable to the payment of rental charges.
I never used vPost before so i dunno how cheap is cheap