I actually waited in line at a bank for about 15 minutes once, and when I got to the teller the manager said "hey - want a coffee?", and handed me a Tim's card (reloadable gift cards for Tim Hortons). I had no idea what the value was - but it turned out to be $2 (just enough to buy any size of coffee at Tim Hortons).

Having it be $2 was a lot more useful than having it be for a large coffee - I don't drink coffee, and I ended up using the $2 to subsidize a bagel.