Hi Geoff
This looks like the kind of project Toolset is well-suited for.
Note GeneratePress is one of our recommended themes and works well with Toolset: https://toolset.com/documentation/recommended-themes/
You would set up the Store post type and Coupon post type in a one-to-many (or parent-child) relationship, where many coupons can be linked to a single store.
You'd add custom fields to each post type as required, and can create a custom taxonomy for the store categories.
These are all part of the core Types plugin.
To display coupons on the store page, you would make a custom template for store posts and insert a view to display the coupons. You tell it which coupons (i.e. the coupons that belong to that store) using a relationship filter.
The View can list the coupons as shown in your mockup.
What's missing is that your screenshot says the link should open a popup when clicked. Views don't have that as an option, the basic options would be to open the link in the same tab or to open in a new tab. It could be possible to have the full coupon post shown in a pop-up, but that would require some effort on your part to work with the markup generated by the View. Support could help you with that, but you would have to be comfortable applying some suggestions for editing the markup and using shortcodes.
You would be editing the template for stores in blocks. If your email signup can be inserted as a block then there should be no problem adding that. Likewise the FAQ section at the bottom.
Except, while you can dynamically output fields such as the store name and even the count of coupons belonging to the store, your text shows "found savings 34,915 times" and I'm not sure where that 34915 figure will come from, it could be that you need some custom logic to generate that.
Finally, for importing content, you can use 3rd party plugins to import posts and custom fields.
If you need to import relationship data (e.g. you want to import coupon posts and have these be automatically connected to the correct store post) then you would likely need to use a paid solution such as WP All Import Pro which has an add-on specifically for Types relationship data.
