EDIT: I still see it as being available at fashion valley for Verizon.
Around 3:30 local time. It was at fashion valley
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That chrome extension is horrible. It alerts even if the ads refresh which is very annoying. So it will keep alerting you every 5-10 seconds lol
Alright, here is how to do this.
1. Install page monitor (https://chrome.google.com/webstore/detail/page-monitor/pemhgklkefakciniebenbfclihhmmfcd?hl=en)
2. Go to iphone checking page (http://iphone-check.herokuapp.com/) --> enter your zip --> submit
3. Select the page monitor button and then choose "monitor this page"
4. Right click the page monitor button --> go to options
5. Find the page you are monitoring and check off "advanced"
6. Change the check interval to 10-30 seconds
7. Select "custom mode" and it should be set to "selector" by default
8. Select the "pick" button --> this will bring you to the page you are monitoring
9. Hover over the table with your mouse and you will see that it will start outlining the section that it is monitoring. Move the mouse in a way that it selects the entire table.
10. Press done. This will make it only monitor changes within the table and not ads changing.