Retrieving data from website - Parser vs AI
It depends what to use on what you are doing. I divide this problem in two categories.

1.Site without changing structure

Suppose, you are building a app which takes data from your national weather department site and normally which has same structure throughout decade. Here using AI for finding data is stupid thing. You should use conventional parsing technique here. and also your are getting data from number of sources but has fixed structure then you can go with this approach.

2.Site with changing structure

As per your example, I believe approach 1 is not so useful. because there are lots of site to parse and these site changes there structure periodically. So I believe using AI for parsing data from these sites is beneficial. I believe you used Optical Character Recognition. you will need similar functionality to your system. Your AI system first load page and see how it looks in browser (not code). Then finds appropriate fields from page using Named Entity Recognition from text which found using OCR

I think applying Named Entity Recognition to directly parsed code is sufficient to find different fields like item name, price, specifications, type etc