Google is now testing adding labels to the product detail side panel when you click on a product in the Google Search popular products grid. The labels spotted include a "most popular" and "best price" label in a blue background.
This was spotted by Brodie Clark and posted on his SERP Alerts on X and notes page. Here is the screenshot he posted:
I cannot seem to replicate this but these labels to make these products from these retailers really stand out amongst the others.
Forum discussion at X.