If it's above RM500, you'll probably need to pay. Perhaps some experienced importer can give some suggestion.

Hi,

It doesn't matter whether you are ordering loose Lego parts or new/used sets. As a rule of thumb, once you cross the RM500 total value (value of the Lego + shipping) you will be subjected to 10% customs duty.

Let's say that your combined order value plus shipping cost is below RM500, your stuff can still be detained by customs if the customs declaration form by the seller isn't clear... Or customs suspects the value of the goods is higher than what is being declared in the declaration form... You really don't want to get into the situation of false declaration as it becomes a legal matter. Sometimes customs just want you to produce a copy of the invoice as it may be missing in the parcel, if it is below RM500 they will release it once receiving the invoice.

Hope this helps.
Not meaning to steal Tun Alby's thunder, it's been awhile since my last haul and these 3 boxes were delivered by UPS this morning...