You can think of K c as the expected return rate you would require before you would be interested in this particular investment at this particular price. Here is a calculator to let you try it out. You can find values for beta online at Market Guide and other sites.
Analysts sometimes use a more complicated value for beta, that grows with a company's debt level.
There is also lots of controversy about whether beta, which measures past volatility, is sufficient or even relevant in predicting future risk. William Sharpe, who invented CAPM, discusses these issues in an online interview . If you get creative enough with the discount rate and long-term growth expectations, you can come up with some wildly unrealistic valuations. So if you do use this approach, you should check your results by using discounted cash flows the traditional way, just to make sure you aren't fooling yourself.