Tea and silk are more valuable, by size, than beads - one bead of this particular size and quality will get you a simple meal for one, most places. These beads are worth about half that; there's beads worth up to about ten times that. A night at a safe traveler's inn usually costs two of the larger beads. The cheapest tea block is worth around twice that, but the tea blocks are meant to be easily divided, and nicer ones are a denser way of storing worth. This particular copper coin will buy five of the simple-meal-sized beads.
(She's low-balling her prices, but seems to believe she's still giving him a good deal.)
This comes out over a meandering conversation, mostly involving her but with the others chiming in as well. This inn charged such-and-such but had the most wonderful food, and exquisite company... Tea and silk are rather valuable in the Land of Iron, did you know they don't even have ninja there... Copper's mined in this handful of locations, and she's been all over the continent this trip, and is set to head home soon... Of course, she'd also love to hear where he's from, and what sorts of things they have there. Exotic trinkets always go over well in Uzushio, since travel off the island's so hard. And if he's looking for something else other than just basic commodities, well, she does have assorted trade goods unique to Uzushio left over.