Money, a medium of exchange as opposed to mediums of distribution; ie vouchers, tickets, coupons, ration cards, tokens, or even tabs. Not to mention gift economies and honor systems. There's a decided historic difference between the underlying ways mediums of exchange work vis-a-vis mediums of distribution.
McCoy was just griping after getting his butt whupped in court. You don't think he really owned a whole planet? And even if he did, then he should be quite self-sufficient from any external economy, though maybe not from a local legal system in his sector. Oh, and you can still have material possessions in a moneyless society as I've already indicated.
"...and that despite endless economic textbooks to the contrary, there has never been an economy based on barter: that actually-existing societies which do not employ money have instead been gift economies in which the distinctions we now make between interest and altruism, person and property, freedom and obligation, simply did not exist." David Graeber - Fragments of an Anarchist Anthropology (.17).
Kirk was just making a generous gesture to Uhura.