I think you'll be best served by reading a general book on pricing - I tend to recommend The Strategy & Tactics of Pricing in one of its various editions. Some of the authors' experience contradicts my own, but then all pricing wisdom is highly subject to change as markets change.
Meanwhile, your question really has two components.
First, there's explicit pricing: how do you communicate product and service pricing to (prospective) customers? The best way to answer your own question is to look at comparable propositions to your own and systematically record prices. In cloud-based services, it's commonplace to provide a range of 'products' that are primarily differentiated by price, which may also be executed by varying feature availability, technical limitations etc. So mapping tends to be relatively complex in detail - but the object of the exercise is about structures so it's less important to be 100% comprehensive and accurate.
Second, there's contractual pricing: if the explicit pricing is incomplete, how are customers actually charged? And you're right that even discovering this may apply means trawling through every document that forms part of the customer contract - some of which may not be available online. Again, you don't necessarily need to get all the details, but it can be illuminating to find out where a company reserves the right to vary prices to a particular customer, and to dig into the reasons (e.g. Is the company covering risks in areas where it may incur third party costs? Is it exploiting specific niches with little competition, or digging into specific highly competitive niches?). Again, you are the person best placed to work out the relevant market areas to explore.
Regulated markets often will have explicit requirements to price in certain ways (either for all players and all offerings, or for certain players / to certain customer groups). The regulator is the best source of information here. It's usually straightforward to understand regulated B2C pricing, but often pretty arcane in B2B and especially wholesale markets.
Good luck! Pricing is fun, and the possibilities are endless!