Given that: - ATmega328P AVR CPU is ~$2 / 5k units - a 64 x 48 monochrome OLED display is ~$2 (<http://www.aliexpress.com/item/0-66-inch-oled-64-x-48-Amoled...) - Given its small size and simple shape, I estimate the mold for the enclosure to be ~$2000, so < $0.50 per unit

We are speaking of a $5 cost. Ok, let's get a margin and double this figure.

Even counting for Premium Worldwide shipping, I can't reach the listed price.