Scan Tool?
 

I am a pretty decent DIYer. I like to do as much as reasonable myself.

I am looking for a good scan tool for general stuff-like reading all the modules, resetting a few things here and there, and maybe even up to reflashing modules.....

I'm confused about what gives the most bang for the buck. Seems to be a vast variety of scan tools available, and I'm confused.

Is there a good DIY scan tool that will provide good capability for under or around $500? What would be the best for capability relative to price?

I don't have this, but it's probably what I would buy if I were starting over. I have a few lesser ones that get me buy, and Techstream isn't hard to come by, but for all around this is what I'd recommend.
I trust this guy and his advice!

What year of car?

Look into Techstream software which is what Toyota dealers use. It can be downloaded then used with a laptop or phone via a dongle or WIFI ODBII dongle. With this software one can change the settings of lots of things or what they call code the modules. The software can be found for a low of around $20.

If you are just trying to read codes take note that Toyota like other car makers has in addition to the generic OBDII coding their own coding which is more detail. Thus if getting a scanner get one that has in addition to the generic code reading it can read Toyota codes.

The Toyotanation.com website has a list of scanners their members preferred. Search the web under "toyotanation ODBII scanner" for hits.

Look into Techstream as it seems to do it all but take note of any needed updated versions for your year of car.

Otherwise look into Foxwell NT710 for Toyota, Lexus, Scion or something from Autel.

great advice