Sites that organize deals/coupons on specific items to show you where to go for the best price?

I think I saw a site like this, but just for juice. All it's supposed to do is list prices for certain products from tons of different sites so you can find which sites have the product you want at the cheapest price.

The closest I've came to finding something like this was https://www.cheapvaping.deals

Any ideas? Thanks, fellas.