It's best to mail perishables early in the week. Wait till Wednesday and you're practically guaranteeing the box will languish in the mail room over the weekend. Pack sturdy cookies, such as chocolate-chocolate chip, oatmeal or molasses, not Snickerdoodles. And a moist little loaf of banana bread or pumpkin-chocolate chip bread will arrive looking - and tasting - as perfect as when it left.
Wrap breads in plastic wrap, then foil, to seal out any air. Some people go so far as to wrap cookies two at a time, back-to-back, but who has time for that? Instead, stack them cylinder-style and wrap carefully in plastic wrap, then foil. Or, pack them into a Tupperware-type box, placing a layer of wax paper between layers. Pack everything in a sturdy cardboard box, cushioning the baked goods with shredded, crinkle paper, bubble wrap or even crumpled newspaper. (Make it the comics or sports section and the box will hold added entertainment value.)
Depending upon how far that package is going and how much it weighs, the U.S. Postal Service flat-rate boxes may be a better deal than buying or scrounging your own packing materials. The USPS boxes are free and the cost is the same no matter how heavy the contents, which makes it a significantly better deal if you're mailing something from California, say, to east of the Rockies. It's not a better deal if it's a lightweight package going from New York City to Boston, or San Francisco to San Diego. And if you were planning to reuse a box you already had, grabbing a new box from the postal service is not exactly a green move.
Finally, a couple of dozen cookies and a mini-loaf will please not just your child, but his roommates and friends too. Tuck in a box of hot cocoa mix, and they can have milk with their cookies too.