First thing to know about CVS is it has a store card.  You want to make sure you sign up for it and register it online.  If you give your e-mail address you will frequently get coupons for dollars off a certain purchase amount (for example: $4 off $20 purchase).  CVS has the Extra Bucks (EB) program.  When you purchase an item that is eligible for EBs you will need to pay for your item and the EB will be printed out on your CVS receipt.  It is good on your next purchase.  These EBs expire just like regular MC's.  You can use one MC per item and CVS allows customers to use as many EBs in one purchase as long as the subtotal does not go below $0.  You can sign up here.