Sadly, Excel doesn’t have a stock price formula, but Google Docs has just the thing: a GoogleFinance Function. It updates a stock price when you open a Google Docs spreadsheet.
The GoogleFinance Function has two arguments, symbol and attribute. The symbol argument represents the stock symbol for company or mutual fund. If the attribute argument is left blank, price is returned by default. Both arguments are to be enclosed in quotes.
A list of common attributes — high, low, volume, marketcap, etc. — can be found here, just click on the link: View a list of common attributes.
There is a disclaimer shown that applies to the GoogleFinance Function.
Quotes may be delayed up to 20 minutes. Information is provided ‘as is’ and solely for informational purposes, not for trading purposes or advice.
It’s a shame that Excel doesn’t have a similar function, especially in Excel 2010, but I guess Excel is more about calculation than information.