Recently I heard an ad on the radio for a product called CarMD that would allow you to save hundreds on car repairs. So being my naturally inquisitive self I decided to see what it actually is. After going to the CarMD website it looks like this device is just an ODB-II scan tool . It is a on the high end of price for one but I wouldn't recommend buying it. Simple fact is that an OBD-II scan tool can be had for less than $30 if you really need one.
So why don't you need one? A number of auto parts stores have loaner tools and will let you use a scan tool free of charge. I know the local O'Reilly Auto Part stores loan out tools usually you can just leave your licence and use the tool in the parking lot, or if you need to take it with you you just leave a deposit (the cost of the scan tool) and get that back when you bring the scan tool back to them. Also I have heard ads stating that Advance Auto Parts also loans out scan tools and will even do the scan for you. There are probably other auto parts stores that will loan out the tool as well but these were the 2 that I know do. The reason that they loan out the tool is simple, it is convenient for you the customer to find out what what the check engine light means. The people behind the counter know what the codes mean and can tell you what part you need to fix your car so they get a sale out of it and you leave a happy customer.
The only reasons that I would recommend purchasing one of these tools would be if there wasn't an auto parts store near me that doesn't loan the out, or I am using one almost every day. I would say that the 2 times a year or so I need to use one I can spare the 15 minute round trip to the auto part store. I don't have any reason to believe that the CarMD produce is a scam, bad product, or a dodgy company, they seem completely legitimate and there isn't anything magical about a scan tool. For the $119.85 they are asking for a scan tool you could buy an inexpensive OBD-II scan tool (they all read the same data) and about 3 shop manuals that will tell you how to fix the problem with your vehicles.
I am not paid by O'Reilly Auto Parts or Advance Auto Parts, I was only used them as examples of companies that loan out the scan tool. Additionally the scan tools I linked to are only examples, I am not endorsing either of them, nor was I paid to provide links to them. The links are provided for example purposes only.