My wife works at Macy's so this is what she told me...
Most of Macy's coupons only work if you use your Macy's Card.
You may have to look at the small print on the coupon itself to see if it says must use Macy's card.
It will also flag at the register and the salesperson will tell you if you need to use your Macy's card if the case may be to honor the coupon.
The coupon does not work on items that have a price with the last number ending in an 8 (usually EDV Every Day Values) or a manufacturer who will not allow lower discounts such Polo/Lauren etc.. --names are usually listed on coupon
More coupon's are mailed to the cardholder than will appear in the paper.
Also Macy's have several Customer Appreciation Days each month on select items (signs would be posted above the item) you will get additional 10-15-20% off an item if you use your credit card and there would not even be a coupon available. The more you use your card you will earn reward points from further discounts to freebies in the store, such as gift wrapping, percentage back (1-2%), reward dollars ($10-$25 off a certain amount of purchase).
Hope this helps..