You would probably pay for: the replicator, the recipe,the ingredients and the energy used by the replicator. However, Star Trek has a different economy from ours.
Star Trek has no economy except for its fictional one. Their economy of fabricators is itself a fabrication. At best, it represents an ideal.
Which is why the original argument is pointless.
Yes, and software products are the sum total of all of the effort put into developing, advertising, maintaining, and supporting them. The fact that they are distributed as data is an inconsequential fact that obscures what they actually represent, and that is very much a human achievement no different from painting a picture or building a couch. There are tooling costs and all sorts of ongoing fixed costs, just like any other business.
As for Star Trek: when that day comes, we'll deal with it then.
What if everyone had a Star Trek replicator? Would they still pay for products according to their value? That's what a computer acts like.