I've no idea what ''dip'' is but snuff as in the powder you take through your nose should be available in most good tobacconists of which there are several in the capital. I use Tabaqueria Inglesa on Ave Paraguay 553 as they have a decent selection of tobacco products from abroad. Google Tabaquerias Buenos Aires and you'll find more.
well, after waiting what seemed like forever, last week i finally recieved a telegram from correo argentino. the package arrived, so i had to go pick it up there and pay a small fee (100 pesos). i wasn't sure if i would actually be able to get the package but lo and behold i did. so, to answer the thread, maybe you could buy some and ship it here but expect to wait a long time for it. having said that, i live in neuquen so maybe that was reason for even longer delay arriving.