Some things to note :
* The duty is assessed on the "value" of the goods rather than the figure that may be written on any "invoice" produced by the importer. Customs have a database which is used to assess the value so underdeclaring value to avoid duty doesn't work anymore.
* Allowances cannot be pooled, even among family members.
* Do not try to bribe a customs officer to avoid the duty unless he asks you for a bribe first. The penalties for being caught initiating a bribe are quite significant and unpleasant nowadays.