How do you calculate and decide the "right" amount to save?

I'm a college student and have heard so many different recommendations for saving money, and I'm trying to understand which is the "right" amount to save.<br><br>So I'm 21, in college, and earning about $4000 / month, after taxes. I don't have student loans or other debt, and I'm not married or have kids. My goals are to have a steady income, a house, and retirement savings. I don't want to be anything more than upper middle class.<br><br>The advice I've heard goes all over the place, and seems to conflict. Kevin O'Leary said, "Try and start early with retirement savings. Just 10 bucks a month in your IRA if you have to." Which sounds good, but I don't really have an idea how to work retirement into my budgeting. Suze Orman said the no brainer rule is, "It doesn't matter what you make. It's what you keep that matters. Always put aside 50% of what you make, and invest it."<br><br>I know sage money advice is to live below your means and to save, but "save how much?" also matters. And how do you factor in retirement? The 50% thing seems extreme and unrealistic, but I'm really eager to learn about setting up a budget.