These contain mostly drinks, but in some areas hot + cold meals, and even T-shirts or electronics.
Drinks range from 100¥ – 200¥ and many of them are quite good, such as BOSS Coffee, shown below, CC Lemon, and lots of teas. Some also feature the usual western soft drinks – although most western soft drinks are not as popular in Japan as they are in the west.
You will find these machines on virtually every corner or shopping complex. Some take only coins, some take bills also, and newer ones also aceept the Japaneese train system’s IC card – Suica. The light green machine in the photo in the lower right corner below is one such Suica machine at a train station. To pay for a drink using Suica, just slap your Suica card on the IC card reader and you’re good to go.