I also same thing, got letter from them. Go to PPL show the actual invois which costs less RM500, goods release no tax.
Lately, KLIA customs new people ka.....  normally they release from there but now many things DITAHAN walaupun declared less RM500. Trouble to go PPL JB just to show the actual cost only.

   

I ask the PPL people, they advise to print the purchase invoice from internet, also payment proof e.g paypal ka, TT slip Westen Union ka or anything yang berkaitan. I show that one la, just to proof for Kastam people saja. They ask to open the package and inspect then confirm not drug, bomb or nuclear explosive items, then release.
About free gift, never had experience. But maybe ask your friend there to write some sort of delivery sheet, print and show them? Boleh kot? 

All documents regarding purchase and payments, must exactly like the goods inside.
Wait for their letter. Once reach PPL, the custom will issue a letter delivered by pos either Poslaju if EMS, normal pos for Registered Parcel. No letter, difficult because kastam not finish recording yet.
Total cost include Shipping, if more RM500 nego with them the cost for tax. I don't know how much.