Add markup to your product pages so Google can provide detailed product information in rich Search results — including Image Search. Users can see price, availability, and review ratings right on Search results.
Using markup to enable rich product results lets you attract potential buyers while they are searching for items to buy on Google or images that include products you sell. Maintain the accuracy and freshness of your product information, so your customers find the relevant, current items they're looking for.
Read more https://developers.google.com/search/docs/data-types/product
I have included all data that need for product : name , image, reviews, offers( price, date end, inStock or not ), sku,model,id,book id, mpn , reviews etc.
If there is discount for that product it is included and date end
Check more http://demo.plusmotiv.com/productultimate/admin/ login with admin / admin
You can test links from my demo site here https://search.google.com/structured-data/testing-tool
Check here LINK
and than press PREVIEW