Luke, can you ship through the US Postal Service? They offer international shipping, and the (admittedly few) times I've used International Priority Mail, it's beaten the crap out of FedEx/UPS/etc pricing.
Sure, it takes about three weeks to get anywhere, but it comes with tracking and a guaranteed delivered-by date (which is more than you get with International First Class -- on both counts -- although I've heard you can get tracking with First Class if you ask them to do it Registered... that's not confirmed tho).
Not to mention that you'd probably qualify for the USPS' "bulk mailer" (read: junk mail) rates, at the package quantities you're dealing with. I'm definitely no expert in that but I can sort of read regulationspeak and legalese, if it's any help, since Mom is a retired attorney -- I was her research assistant for a few years...