Would taking the GRE (when it is not required) be likely to help my application? I want to go to grad school for Applied mathematics, and I have a high GPA in my undergraduate of 3.56 in Applied Mathematics. I wanted to take the GRE. However, they are very costly around $200, which I am not sure if it is worth paying that much to take the GRE. I plan on applying for Graduate Assistantships. If I do not take the GRE, will that decrease my chances for getting into Grad school and a Graduate Assistantship even though the schools I want to apply to do not require the GRE?
If the school you are applying for does not require GRE than it is extremely unlikely that it will make any difference.
Certainly take a look at the discussion on the importance of GRE scores for graduate school admissions; as usually GRE scores most often are used to perform &quot;cut-offs&quot;, not as a competitive measure (or at least with relatively low weight). Thus, if the school decides not to make GRE mandatory it does not make a lot of sense to submit one (especially, if you don't have one ready for other applications).
Some exceptions probably will apply if the assistantships/scholarships have a separate set of requirements (I am not aware of specific cases that would require GRE, but can imagine such to exist) or when GRE is an optional application package item and one wants to strengthen their borderline submission. Even though in the last case, I would spend more effort in writing a better statement of intent.