Don't do it. Life is all about priorities and keeping your focus. Once you start mixing work and studies, both will suffer.
Go hungry, sell plasma, visit a food bank, do what you have to do. But keep your eye on the prize.
There were certainly periods of time where I didn't see friends much, and my husband had to (gasp) cook dinner once in a while, but it was doable, and I graduated with a 3.7 GPA. I'm not a genius, I certainly did my fair share of procrastination, it was mostly just about making almost every day a "work day" (at least for a few hours), keeping things interesting by alternating between different types of work, and finding creative times/ways to study (commuting, lunch break, doing class busywork watching TV in the evening, etc)
I don't think I would have gotten "more" out of the program by quitting my job and just doing that full time. If anything, the financial stress would have made things more difficult.