Hi amitcaagr1,
When it comes to studying for the GMAT, there are LOTS of different options, so you should plan on doing a bit of research into the various options. You have to decide how you learn best (a live class in person, an online class, guided self-study, etc.); the important part is in the expertise and guidance that you'll receive. Most GMAT companies offer some type of free resources (practice problems, Trial Accounts, videos, etc.), so that you can 'test out' a product before you buy it. I suggest that you take advantage of all of them, then choose the one(s) that best match your personality, timeline and budget.
What is your score goal?
When are you planning to apply to Business School?
GMAT assassins aren't born, they're made,
Rich