http://www.diapers.com/ has gdiapers and free shipping over $49. They don't ship to APO, but you could ship to a friend/relative in the States to forward. Also, they are in more and more stores now, even a grocery store in Erie, PA, not the most progressive town by any means, so if you have a friend/relative who could buy them at the store and mail them that would reduce the cost. I hate paying for shipping. Many sites that have free shipping deals exempt APO, probably because the USPS is such a pain to deal with as opposed to UPS of Fedex. Very frustrating.
I just ordered my son some shoes and decided to order two pair (in different sizes) instead of one to distribute the cost of the shipping.
I ordered a stroller in March and it still hasn't arrived. The company is waiting for another to come in so they can send a replacement shipment. I am grateful to have the APO, but I do miss fast, hassle-free, free shipping from UPS and Fedex.
I do have gdiapers, but since we moved back overseas (Korea) , I have been using my cloth diapers (Bum Genius and Fuzzi Bunz) and Natural Choice better disposables (chlorine free and made of corn) for the CDC, which are available at the commissary here.
Maybe you could request them at the commissary. If they get those starter kits and then the refills maybe others would start using them.
Good luck!