I'm picking up a per diem job in allied health, doing a few weekends here and there. At 300 bucks a 12 hour shift, it's more than worthwhile, and really helps pay the bills. So it's totally doable, you just need to know where to look, and have skills that are conducive to casual and per diem work. Scribing on weekends, EMT, ED tech, CNA, and pharmacy tech positions tend to be more weekend and casual friendly, at least in my area. What it really comes down to is whether certain jobs are worth the income they net you. Can you still get great grades, study for the boards, and knock out your ECs while working a given job, and is the pay enough to make it worth your while?