I don't like to advertise for companies, but Matlab recently released its 2012 version for students and I know that a lot of students don't realize how much computational bang they can get for their buck. The parallel computing package for Matlab only costs students $29 and allows them to run parallel code on an unlimited number of cores. (Compare this to Stata, which charges hundreds of dollars per additional core.) And even more importantly, parallelizing your code is amazingly easy (in the best cases, it may only involve changing your "for" commands to "parfor"). As a PhD student, I think this $29 investment saved me several months on my dissertation (I'm not kidding).
I'm guessing there's a similar free package for R which I don't know about (please comment).