Graduate students (Master's and Ph.D. candidates) at KAIST can join SIAM for free. These memberships can be renewed for up to six years as long as the member remains a student at an eligible school.

Apply here:
http://www.siam.org/membership/individual/free.php

SIAM is the "Society for Applied Mathematicians and Computational Scientists".

* KAIST is an academic member of SIAM. (http://www.siam.org/membership/academic/academic_members.php)