When posting items wether within same country or overseas, I have found the pre-paid satchels or envelopes often workout far cheaper. This way you can post your presents to family or friends, or even paperwork faster & cheaper by using pre-paid. In Australia where I live there is satchels that

one will hold up to 3kg's & costs unedr $10 to anywhere in Australia.

I post a lot so just thought I would give this advice