Finding online real time stock quotes that are truly free can be difficult. Many of the online discount stock brokers do offer real time quotes but they aren't free as you have to pay a monthly fee to get them. For people who trade only once in a while, it is hard to justify paying that fee for something that you would think should be included with your account.

Over at Yahoo Finance (free) though, you do get real time quotes, or at least as close to them as you can get. See the picture below with the small blue "real time" quote of -$2.85 which is about a dollar better than the $3.82 you see in the body of the data. Usually, where ever you get your quotes, you would only see the $3.82 price.
You must understand though, that the market moves so fast that no stock quotes are really "real time". They might be close but never up to the second. However, the 20 minute delayed quotes that you get most of the time at most financial sites are now a thing of the past if you use Yahoo Finance. Whenever you have a volatile trading day or a stock with breaking news that you are interested in buying or selling, it does help greatly to be able to get quotes that are real time and free.