Most often students are left with two options in mind, should I go for Job or do an MBA soon after their Graduation. The answer to it is quite simple, if you have a stable job on hand, you are better off to work for 3 years and then take up competitive entrance tests such as CAT, XAT or GMAT and do MBA with work experience.
Stable Job? What you should consider as a stable job? - Don't go for a Job if you think it doesn't suit your career objective, don't do a temporary job such as Teaching or BPO, if that is not your long term goal. You will be struck with work which you mayn't be interested to work and force yourself to quit sooner or later. Go for a core job even with a less pay and trust on good companies, who treat employees well.
It is important to research about the Company and the Job profile that is offered to you.
Conclusion: Go for Job if the Job is from a good Employer, else go for your Masters.