"5-0 and go" (pronounced "five oh and go") refers to the mindset of not caring about achieving a certain standing in a class or program but instead merely wanting to attain a passing grade and move on with one's life. It assumes that a passing mark is 50 per cent; different institutions may have different standards.
I have no idea where the phrase originated, and many of the Google results for it — even as an exact phrase — are sports related (think things like "the team improved to 5-0, and go on to the next round"). Filtered searches that block sports-related terms yield very few results, most of them blog posts from students discussing classes they just wanted to pass.
A "5-0 and go" attitude obviously has ramifications for a student's future; it may get you the diploma or degree, but it could limit future options (such as eligibility for graduate school).
I have been somewhat guilty of this attitude at certain points in my university career, though I did aim for at least a 60 even when I hated a course and just wanted to be done with it. I'm kicking myself for it now; had I worked a little harder in a few classes, my GPA would have been good enough for most graduate schools. I don't know whether I would have gone, but it would have been nice to have the option. Instead, I finished with an overall B when I probably could have had a B+.
In short, a "5-0 and go" attitude may make schooling a bit less stressful, but it can also obviously limit your options.