This is a minimalist desk lamp designed by Finnish designer Timo Niskanen: the Deposit Lamp, where the switch is the one-dollar deposit you put in.
Many people forget to turn off the desk lamp after using it, causing energy to be wasted bit by bit. In response to this phenomenon, Timo Niskanen designed this coin-operated lamp. You need to insert a coin into the notch on the lamp's body for it to turn on, and when the coin is removed from the notch, the lamp turns off. This encourages users to take their money with them after using the lamp while also turning it off, thus conserving energy.