It could become some niche search engine but I don't see any money at all involved. Nobody is earning commission on half a loaf of bread. There's no money there. There are already store stock tracking websites for many profitable products (like photography equipment) and general search. The half a loaf of bread niche is a guarantee that there's no money in this particular site.
For example, I look for photography equipment prices (in canada) using photoprice.ca, which scrapes canadian camera stores that have their stock online like henry's or broadway camera, as well as comparing against amazon.ca, amazon.com, and US stores that ship to canada like Adorama and B&H.
The issue is just 'is the data available'. None of that makes it profitable if it's just loaves of bread.