I have a 2004 F-150 and just spent $84 on a cleaning of the throttle plate/butterfly at the intake and have the P506 code cleared!
I could have done this easily myself if I had a OBD II unit. Anyone care to suggest a model for my personal use? Will I need a code book also?
It would also be used on my wife’s 2012 Focus?
If you have an Android tablet or phone, download Torque Pro, and then get a bluetooth OBDII reader off of Amazon. Should be less than 25 bucks for the reader, and $4.95 for the software.
If you don’t have an Android device, get one 
You can get the reader, Torque, and an inexpensive Android tablet for less than you would spend on a decent OBD reader.
You won’t need a code book - it will tell you that stuff when it finds the codes. It will also give you real time engine parameter monitoring (exactly what is measured will vary depending on what the specific car’s ECU will output to the reader, of course). You’ll be able to see things like your fuel curve in real time, there’s a free addon you can get to monitor for engine knock, all sorts of stuff.
Does it output advanced error codes like the $1000 units?
Give me an example of what you consider “advanced” error codes and I’ll try to tell you.
However, it is obviously not going to be as good as a professional code reader - - but if OP is talking about saving $84, he’s probably not in the mood to spend a grand on the reader.
Since my corolla does not have a tachometer, I got a Scangauge that mounts on the dashboard. It displays upto 4 gauges that are customizable (I’ve it set to show RPM, water temperatur, mpg etc). It will also read and reset check engine error codes.
I’ve heard some mechanics say that for some error codes, you need advanced scan reader or a dealer level reader.
Autozone and others can read the codes except for the more advanced manufacturer codes. You just don’t get that with cheap units so sometimes its just worth the $100 diagnostic fee at the dealer to determine the cause. That’s the nice thing about Onstar and others, you call them up and they tell you what the code is and you can talk to a technician about the probable causes and repair.
For manufacturer-specific codes with Torque, it depends on the vehicle. Some cars are readable, some aren’t, as Torque’s database gets filled in.
The real-time customizable gauges are available in Torque.
Bing, it doesn’t matter what you read or what you read it with. If you take the car to a mechanic, you are going to pay the $100 to read it anyway. That money is saved only if you do the work yourself.
You can buy a USB to OBD-II cable and a free diagnostic program on eBay that will turn any laptop into a powerful diagnostic tool…Less than $30…I imagine todays tablets can do the same thing with the proper cable…Here is one, there are many…