The vast majority of people would make as much money as they could. Quickly, the economy implodes. People soon realize they can exchange their matter replicator for eggs. A new billionaire class arises, using their millions of matter replicators to make basic necessities for the worker class. The modern assembly line is now just row upon row upon row of matter replicators. One man per warehouse, just moving from matter replicator to matter replicator.
A few smarter people used their matter replicators to make more matter replicators. Lobbyists quickly pass “safety regulations”, and these “black market” replicators are outlawed. Soon local police start advertising “amnesty”, where you can bring in your illegal matter replicator and exchange it, no questions asked, for a gun.
A few unlucky people used their matter replicators to make drugs. The purity of replicated drugs quickly renders these people unable to continue using their replicators. These replicators are collected by next-of-kin, stolen by the people that exchanged their own replicator for eggs, or accidentally destroyed.
I’m not sure how common this knowledge is, but the default Lemmy web-interface sucks. There are web portals that improve it considerably. Some of them may be available direct on your instance. If not, I use https://alexandrite.app/ for my frontend.
There are others, at least one of which looks like old.reddit, but I’m not sure the address of them. I would trigger Cunningham’s Law, but I don’t want to add confusion.