First, you need to sign up for their Extra Care Card. The cashier has the form at the register. This is a customer loyalty card and gives you access to the sale prices advertised. 
Second, you need to visit the coupon kiosk, also lovingly referred to as the "Magic Coupon Machine". The kiosk is usually close to the front of the store. Every time I shop at CVS, the first thing I do is scan my card at the kiosk. It prints in store coupons or even $ off your purchase. These are CVS coupons and can be "stacked" with manufacturer coupons.
CVS offers rewards at checkout called Extra Care Bucks (ECB's). They print on the bottom of your receipt. Like a Register Reward at Walgreen's, I view these as "wildcard" coupons when I shop. They can be used towards your next purchase.
When I shop, I focus on items my family uses and/or offers ECB's. Once I get one EB(or more), I continue to use them to purchase other items that offer EB. That is what keeps the out of pocket expense at a minimum.
