Here is a tiny name tag that you can use to display prices and messages anywhere you put it. The Coolbird Bluetooth LED Name Tag is compatible with iOS and Android devices. It has a built-in magnet, so you can attach it easily. It runs for 10 hours on a 210mAh battery.
This app connected name tag has 44 x 11 pixels resolution. It has 3 brightness levels. You can display short messages, logos, and numbers on this name tag. More info is available here.