SoulLi
You can pony up 10 dollars for a stud finder that is more accurate than magnets. They dry wall nails you snag with a magnet isn't in the center of the stud. If you are going to hang a tv, I suggest you do it right, you don't want your investment falling.
And you're guaranteed to hit the center of the stud with a stud finder? I don't think so. Stud finder or magnet method, most people have about the exact same chance of hitting the center of the stud. Most studs are typically only an inch and a half wide, the dry wall screws typically aren't much more than a quarter inch to half inch away from the center.
I realize that stud finders aren't exactly expensive, but I was just offering up an alternative method in case OP didn't want to or couldn't acquire a stud finder. There is no reason for you to attack it and say it's not the "right" way. It's merely an alternative that for most people is just as accurate as a stud finder.