I'm not sure exactly how it's going to shake out because I can't find the list of which countries are in which zones, but right now it looks like the lowest cost for one polish to ship internationally will be $7.35, and the highest zone is $9.15. Two to three polishes will be between $8.55 and $12.15. And, of course, the costs just go up from there.
I may need to suspend international shipping for a bit while I figure all this out. =\