To the original poster: I have worked part-time for a good chunk of my Master's program (full-time school) and I was able to manage it, mostly. It was still difficult and I often reluctantly had to ignore my social life. Everyone manages their time differently though so perhaps it's best to just try for it and see how it goes.
I had first considered doing full-time work and part-time school but realized that in that situation -- full-time work -- my job would always come first, and I just did not want to do that, sacrificing school, seeing as I wanted to spend my time/$ in graduate school doing my absolute best. I did not major in history in undergrad, so I feel as if this is my one chance to prove myself for PhD applications.