On Star Trek doesn't everyone have their own Replicator than can churn out anything?
Why does someone even need to get paid? Just make one from your replicator and ship it to a friend in need.
Just use your replicator to make another replicator and send them that!
Give a man a fish and he'll eat for a day. Give a man a fish replicator...
I'm not sure if this is serious, but I'll risk the miss and say that they addressed this in TNG, saying that humanity evolved past the economies of earlier times.