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> On a more microeconomic level, what happens when Bashir and O'Brien order a couple rounds at Quark's? Who picks up their tab?

It is mentioned in the article that the Federation would likely hold reserves of foreign currency (like latnium) for trading with peripheral civilizations. It's likely that being stationed on an alien space station would give the DS9 officers some stipend of latinum for trading with the locals.

It could also be that Sisko worked out a deal with Quark that rent and maintenance is free, so Starfleet officers drink for free.

Or like he also said in the article, drinks are just a loss-leader for the Dabo table and holosuites.