This doesn't appear to have an actual alert system, and the reports are very simple compared to Google Analytics of Shopify's base reporting.
Lincoln City Gifts
Seems to focus more on analytics than sales. When I tried to install it, The icon changed to something different and the app asks you to set up an account. You have to link your google analytics to the app even though you're using it for shopify.
Pure Hearts International
Installed easily. Now it's going to give me free, helpful info? What could go wrong? Nice. :)