A) USA, most importers not charged tax unless an invoice value over $1800 with express like UPS, DHL, Ems;
B) West Europe like Germany, France, UK, Spain charged tax by 30% of invoice value, and there is a minimum value like $30 or $50 once they feel a box big enough to charge, if box too small, they ignore with express,
C) South American importers are experiencing a hard time with DHL or UPS for their orders, their government is having heavy tax on importers like Brazil, Argentina...on the other hand, shipping cost is a headache... so let express away from it, but with Ems or normal mail...or 60~80% tax!
D) African custom seems reasonable as long as tax charged
E) East European countries suffers hight tax besides shipping expenses..for people there, better to use normal air mail, it works