Auto Zone and Advanced Auto will read check engine light codes for you for free! I get it done all of the time! I always ask them to write it down or print it for me, they do this in hopes that you will buy parts from them. It only takes 5 minutes for them to do this!
Also, sometimes you can get them to clear your code for you, they are not suppose to but some will if you explain to them you want to see if it was just an intermittent thing or if its persistent!
Good Luck!
Lisa