This is an option (not enabled by default) that can be selected to let users be informed on the Coupon details they are using, during the first and the following logins to the SSID.
To do so, access the Splash Page Editor, select the desired Splash page and enter its Settings menu.
Now access the Authentication -> Coupon section and enable the Show Usage option, under Coupon Authentication Settings, and click Save to confirm, like shown below:


From now on, the user will see the a recap of the Coupon he used at the first login.
The same information, with the coupon's time/quota left will be available every time he will re-connect to the SSID (after the Session time-out expiration), like shown here below:

Enabling the "Remeber Me" feature, that allows automatic re-login for returning users, the Welcome Back page with coupon information will appear every time user re-connects and he only needs to click the Connect button to surf the internet

Related Article
Wi-Fi Couponing System: overview
How to enable Remember Me on your Classic Hotspot Account