Creating a custom "product" content type?

Let's say I want a web site with various products on it. I know a database driven site might be a better fit for this but if I want to do it in grav, does it have support to create a custom content type such as "Product" with fields like:

Name
Description
Price
Weight

Product is just an example it could be any custom content type.

From what I've read you can put these fields in the header section of a page, is that the best way to do it in grav? I also read something about blueprints, does that apply here?

Is there support for having the data in a json/yaml file and generating the pages on the fly. I wouldn't have a huge amount of items but it would still be 200 to 300 items so creating 200 individual folders and pages seems tedious

You might want to look into https://github.com/trilbymedia/grav-plugin-flex-objects. Haven't used it yet, but it seems to fit your use case.