Yes I agree, if you are shipping diapers and wipes, you may want to consider other things, snacks, little goodies, etc.
If you use garden grocer or do a grocery stop, you can have beer, wine, milk etc. also.
I almost always ship a box of snacks and treats, since DS has food allergies. It's good to be prepared when traveling with a baby!
I use USPS usually, and I think there must be a cheaper way. I heard FedEx ground is reasonable.
Do include your name and reservation number and check in date clearly on the box as well!