They are one ticket per drink, that has a value of $3.75 or less. Some times
the bar staff do not understand this limit and allow the purchase of higher priced drinks. We used them on the Sensation in September, and except for the saving of the 15% tip found them to be a bigger hassle, again because the bar staff had no good understanding of them. Many times they tried to charge the drink to the sign and sail and take the ticket.
The biggest advantage to us was the ability to spread the cost of the cruise out over two credit card billing cycles.
I was on the Truimph on July 1, and the only time I charged a drink to my sail and sign was when I purchased the drink of thle day in the special glass that you get to keep. Otherwise, had no problem with the coupons, always had a frozen type drink, which I think cost more than the $3.75.