Bring your morning receipt back after 2pm to get an iced grande for $2.50, now thru 8/9. #TreatReceipt (US & CA only) pic.twitter.com/ORWDQLoCMl

— StarbucksDeals (@starbucksdeals) July 27, 2015

And in a nod to modern times, if you don't have a receipt because you used the app to pay, you can just show the barista the transaction time stamp on your app.