Yahoo is very easy to use and provides customized data. Use the following page to learn more.
finance.yahoo.com/d/quotes.csv?s=AAPL+GOOG+MSFT=pder=.csv
WARNING - there are a few tutorials out there on the web that show you how to do this, but the region where you put in the stock symbols causes an error if you use it as posted. You will get a "MISSING FORMAT VALUE". The tutorials I found omits the commentary around GOOG.
Example URL for GOOG: http://download.finance.yahoo.com/d/quotes.csv?s=%40%5EDJI,GOOG&f=nsl1op&e=.csv