I bought this a few years ago for a different car to decode an engine light. It also delivers current running stats to your device with the app.
Here are a few photos to see a few things it can read.
Depending what your into you could have your phone in a holder and keep an eye on how your car is running.
There are some on eBay.
OBD2 or they can have another name starts with elm I think.
It was about $25.
I had to get one that was compatible with a Holden(Aussie make) but it is easier to get for any other car.
Cool toy and can be handy if you get an engine light on.
Good to have for long trips if you throw a code error you can see if it is time to panic or carry on.
It just plugs in under the dash.
I shopped for one with an on/off switch. It can be switched off instead of pulling it out.