47 years after first experimental AR device known as The Sword of Damocles (1968) everyone can experiment Augmented Reality applications with a smartphone and … a cardboard device.
source: Recombu
How to get (or make yourself) a cardboard device is fully explained on Google Cardboard site.
Several manufactures have their own cardboard/plastic device with less or more options. (Choose the best that fits your needs).
Augmented Space - Espace Augmenté 