Have you ever created an in game reason for why you can shake down a frog for 13 gil?

Maybe they hoard the items of travelers who came before you, or took the loot from weaker enemies. Do frogs have pockets?

Of course, the real reason is so you have a way to buy items from shops while you altruistically save the world. It's just one of those things I think about, like how nobody has a toilet.

At least Final Fantasy VIII gave you a salary :^)