There are special rates available for students and residents, and for members from low-income or lower-middle-income countries (according to the World Bank).
Discount details for:
AO Trauma https://aotrauma.aofoundation.org/membership/member-privileges
AO Spine https://aospine.aofoundation.org/membership
AO CMF https://aocmf3.aofoundation.org/membership/join-aocmf
AO VET https://aovet.aofoundation.org/membership/membership-privileges