CVS does send out previews for its weekly ads, usually three days before the Sunday that the sale week begins. These preview ads are available on the CVS website.
From the CVS homepage, click the Deals icon located at the top of the page. On the column to the left side of the page, click on the tab that says myWeekly Ad. The ad for the current weekly sale will display. At the top of the page, there is an icon called Sneak Peek. Click on this icon to see the following week's sales and coupons. The preview is available no earlier than Thursday for the next week.