Before we get started there are some things you will need to have and know. First, is a box. If you go to your local post office they have free large flat rate box's. Second, also at your post office is a Form 2976-A. This is the United States Services Customs Declaration and Dispatch Note. Do not attach this form to the box but take it with you when you mail the package. It might sound kind of dumb to have to declare something like cookies but you will be required to complete it. You will need to complete the from portion, to, detailed description, the value, check the gift box option , your license # and a date and signature on this form. The last thing you will need is mans best friend, a roll of duct tape. It comes now in white also instead of just gray. It makes any package more attractive. Put the stuff that your mailing into the box, mark the box as fragile if there are things that might break and tape it up good, complete the to and from portion on top and you are now ready to take it to your PO. Using this box will allow you to mail items to a military APO or FPO. To give you am idea of the $$ cost using this box and mailing to either a APO or FPO, I mailed a package to a family member from Murray, Utah and only paid around $12.00. Some of the box's were heavy but price was the same.
Now to give you some information about the military mail system. A primary feature of military mail is that they are subsidized to ensure that military mail posted between duty stations abroad and the home country does not cost the sender any more than normal domestic mail traffic. This means that you are only paying for the item to be sent to New York where the package will be mailed to the military APO or FPO. This is a very good deal.
Overseas military post offices operated or supported by the Army or Air Force use the city abbreviation APO. Overseas post offices operated by the Navy, Marine Corp or U.S. Coast Guard use the city abbreviation FPO (Fleet Post Office). There are also three quasi-state codes assigned to different geographic locations of military mail recipients and also the carrier route to be taken. They are AE-(Armed Forces Europe/Canada/Middle East/Africa)-099xxx. AP-(Armed Forces Pacific)-962xx through 966xx. AA-Armed Forces Americas (excluding domestic and Canada)-340xx.
So when you mail something it should look something like this:
SGT Mike Nelson
Unit 1111 Box 1111
APO AE 09499-0074
The United States Post Office has a very good web site on how to address items correctly to make sure items sent to the troops arrive to them. It also tells you what can be mailed and what can not.