Hello,

I'd like a clarification regarding the different types of purchases available.

I understand that any "individual" purchase I make would give me: access to the content through the search tools, access to it in creation and digital exports I might make. Do these refer to "listings"? As in the spells/ feats/ races/ subclasses/ monsters/ items, all of these searchable "dictionaries"?

Then there's the "compendium" purchase option, NOT as a full product. This is access to the full book, as if I was reading one giant PDF (but it's fully via apps/website, no downloads), correct?

These are the main parts of any one full product that DNDB offers, and together they make up a "final" purchase, nothing to upgrade beyond it?

Thanks in advance

I’m not sure what you mean by “digital exports.”  But “individual” purchases (like the Tabaxi race, or the spell bundle from Xanathar’s) gets you access to those things in the character builder and it the listings (spells, classes, monsters, etc.) you can access from the Game Rules menu above.  (When DDB first started, these were called the listings.  I haven’t seen that term used officially for quite some time, but I don’t know what the replacement term is supposed to be).  

The compendium only purchase is, as you noted, essentially purchasing the book in a proprietary ebook format,which can be read on the website here or download and read in the compendium app.  

And yes, the “full book” purchase contains both the compendium and all the content for use in the listings and the character builder.  In theory one could look at the source bundles as an “upgrade” from purchasing a book/source.  For example, one could purchase TOA, Saltmarsh, and Tyranny of Dragons and later “upgrade” to the Adventure bundle containing all the (currently published) Adventures, but a given source itself doesn’t get “upgraded” past the purchase of the entire source.