Support for Master's students really depends on the school. UCSD, where the author works, provides good support for Master's students. I have a friend who is attending UCSD for a Master's (albeit in Civil Engineering) who has received a TA position that covers his in-state tuition (but has to pay out-of-state fees), and pays a stipend.

Almost all the graduate schools I have researched have explicitly stated whether or not they offer any support to Master's students.