I hate to make it sound like you shouldn't learn though. For example, you could start cranking up ignition timing because you heard advancing it increases power, then get a ton of KR and wonder why your car runs worse than before, and even worse, you could damaging your engine. Last, you really must know how to read live sensor data and what each sensor does and how they react to certain engine conditions before you start trying to tune an ECU. HPTuners started out with only GM vehicles, but they do have a lot for Ford and Dodge now I believe. I'm sure there are others that are cheaper, but many of them are restricted to a certain group of makes and models. I've only used HPTuners, but this was like $700 when I bought it. You buy a tuning package, it comes with software and an OBD2 interface, and connect your laptop via USB to the OBD port on the car. You are correct however about how they work. The closest you'll probably get to that is like a JET programmer if they make one for your car, and those are questionable at best. Also, IMO there's not really a way to get into just a small bit of tuning, at least safely. I'm really not trying to discourage you, but I really doubt you're going to find any tuning software that's even decent for free or cheap.