This is basically for my brother, as it came up this past weekend and I missed my chance to make this point. But I'll make it in public because... well, what the hey. And perhaps someone else might want to jump in, too.
So, I only know of four basic methods for assessing the value of a share of stock, and they all require that you guesstimate some crucial value. But despite that, they are all useful to know and use: