--i hear that packages take a long time to get here. and that if you tape pictures of jesus on the outside of the box, they aren´t as likely to open and inspect stuff. and also that it is expensive to receive because of the taxes to get through customs, so smaller/lighter boxes are best. so, if you are going to send something for christmas (if you haven´t already) now is a good time to. :)
stamps from the US (because i can send things through the pouch if i have a US stamp), books i can use in an english class (ie: simple, rhyming), general conference cds, hard copies of family photos, stickers to hand out to kids (small circular ones with pictures of animals, etc are good), packets of powdered sports drink mix.
--my address: (mission office. for letters or packages)
Hermana Lisa Magnusson
Mission Argentina Salta
Los Eucalyptus 75
Salta 4400
Argentina

Input from Kathleen:
I went to the post office and asked about mailing things to Argentina. They said the Priority Mail Small Flat Rate Box (pictured above) would cost about $12 to mail to Argentina.
My sister-in-law just called. Her son also served a mission in Argentina a few years ago. She said that if you use a Priority Mail box, you don't need to use the Jesus stickers because the Priority Mail Boxes are insured. She also said that when you go the the post office you'll have to fill out a USPS Customs Declaration form. She said that on the form to low ball the value of things included in the package.