Since you're on a Mac, there are some command line tools that can make this a straightforward effort.
curl is a command line tool that allows you to retrieve web pages from the command line. In the Mac terminal, type "curl http://www.yahoo.com" and it will return the HTML for Yahoo's home page.
Yahoo makes it possible to retrieve a single stock quote via HTTP. Using the curl example below, we can retrieve a single stock price from Yahoo Finance. In this case we are retrieving the stock price for Google, whose symbol is "goog".
curl -s "http://download.finance.yahoo.com/d/quotes.csv?s=goog&f=l1"
Yahoo makes it easy for us to retrieve several quotes at once. In the example below we are retrieving quotes for Google, Yahoo and General Mills whose symbols are, "goog", "yhoo" and "gis". We simply separate them with a comma.
curl -s "http://download.finance.yahoo.com/d/quotes.csv?s=goog,yhoo,gis&f=l1"
Now that we can retrieve multiple stock quotes, we need to get them into Excel. The simplest way I have found is to save the results of the curl script in a text file and then import that file into Excel.
To make curl save the results to a file we use the "-o" option as in the example below.
curl -o quotes.txt -s "http://download.finance.yahoo.com/d/quotes.csv?s=goog,yhoo,gis&f=l1"
This creates a file in the local directory called "quotes.txt" which you can then import into Excel.
Note: You can also simply click on the link and Safari will download a file called quotes.csv with the prices.
Hope this helps!
Adding how to import into Excel:
After you have your file of stock prices, you can easily import them into Excel.
On the menu bar, choose Data -> Get External Data -> Import Text File
Select your text file with the stock prices in it
On the next screen you have the options, but just click on Finish
You have to select the cell to place the data and then it appears!