The problem with the two replicators (supposedly) being without any kind of monetary charge is apparently it was big deal for the federation to provide them. So while the federation didn't charge the bajorans, the federation likely was out a financial shitload.
Foreign aid, the bajorans were right next to the cardassians and had territorial hold over the wormhole. The federation might have generally wante bajor in the federation to star, but after discovering the wormhole the federation really wanted to be in bajor's good graces.
So why not give bajor dozens of replicators? Because they're not really all that "free." Each industrial replicator is probably the equalient of billions (if not tens of billions) of dollars.
Nothing to do with finances for the Federation.
It has more to do with what those industrial replicators can do.
They can build large scale objects at a press of a button most likely and in an automated fashion.
It is also not as if the Federation cannot make an abundance of industrial grade replicators... its just that they need to be careful that their technology is not misused - especially with the state of affairs the Bajorans were in so early after expelling the Cardassians.
The Feds also keep a tight track on the technology they lend to others for the very reason that they wouldn't go missing or end up misused (the planet for one thing needs to be unified for the most part and it is easier to keep track of what the 2 industrial grade replicators are used for and where as opposed to 12 of them).
The Feds initially wanted to really help the Bajorans even without knowing the wormhole was there, and they saw them as a potential candidate for membership from the get go once the planet is restored. The discovery of the wormhole however made the Bajoran system a more inviting place indeed, which probably resulted in the Federation offering membership sooner than what originally might have happened.
Since the Federation doesn't use money, its not a matter of measuring the value of industrial replicators in monetary terms.
Its that they can be used for a lot of things on an industrial scale that makes them a highly sought piece of technology almost anywhere.
2 industrial grade replicators are likely more than enough for Bajor. Besides, the situation there was shaky at best in terms of societal and political aspects that its best to minimize how much you send.