To see your rewards coupon(s) on the Fleet Feet app, please log in, and click the "Rewards" present icon, on the bottom middles of the home page. Here you will be able to see the coupons you have earned, coupons you have already redeemed, and available items to purchase using your miles.
To see your coupon(s) on Fleetfeet.com, simply log in here https://www.fleetfeet.com/user/login, and scroll to the bottom of the page that loads. A section called "Rewards" will state whether, or not you have a rewards coupon available. (Note, it will not say how many you have available, as you can only redeem one per online order.)