Notifications for deals on certain products?

Is there an app that can give me a notification for when certain types of items have deals, rebate opportunities, etc.? I’d love to be able to get an alert for when there is a deal on say, the protein bars I like, or diapers/wipes, etc.

I am not interested in building huge stock piles of the same types of items or buying things just because there’s a deal. I’d rather just know when things I need have deals, ya know?