I hate to be a downer, but you are not the first person to try this, and it is more or less a futile effort.
Here is an effort that was started about 18 months ago, and as you can see, has very little data.
Not only that, but with frequent changes to prices, it quickly becomes out of date and you can't trust the data anyway.
I believe there was also an attempt, using a CAN bus scanner (or something like that) that would download nearby Supercharger data from the vehicle in the background, with the theory that if there were enough participants in this project you could get a fairly complete pricing map, but AFAIK it didn't go far.
This effort:
died a fairly quick death it appears.
Here is another thread on TMC that describes some older efforts to compile such a price list/map:
Supercharger Pricing Map?
On the bright side, the OCPI (Open Charge Point Interface -- basically an API for accessing data about charging stations) does define pricing models in its interface, so there is hope that as the industry matures and becomes more open, we may eventually be able to scrape this. But for now, I just don't think this is a worthwhile endeavor. Until we get pricing data directly from the source, derived tables & maps are going to always be incomplete and out of date. And with variable/tiered pricing, I'm somewhat at a loss as to how useful this information is anyway.