Money

"Jason Bradley: Hey, nerd, You forgot to pay for this shit! Jean-Luc Picard: Pay? Bardley: Yea, Pay! Stick the chit in the slot, so I won't take your money by force. Money? It is 2152. Long ago, we were supposed to decide to abandon currency-based economics in favor of the philosophy of working to better ourselves and the rest of humanity. Bradley: Hey, watch it, commie."

Money is a medium of exchange used to facilitate transactions of goods or services.