Coupons: Are mailed (randomly) to neighborhoods. I don't get them, but a friend the next street over does. These are rarely "Rx coupons" , just general Target Coupons
Sometimes in the weekly sales circulular is a coupon for a free gift card with new/transfered prescription.
I assume you may be inquiring about Pharmacy rewards. If you have a Target debit or credit card you can link it to Pharmacy rewards. After 5 prescriptions, you get a 1 day pass for 5% off all purchases. You can combine that with coupons and the 5% everyday discount for using your red card.
In order to get a prescription to count you do have to pay with your read card. If you have a HSA/FSA you can send in your claim after the fact, with your Target reciept to get reimbursed (see your own health plan for details)