Salmon is a rare commodity in Tal Sharnis; it has to be imported from other realities, since there's a dearth of good local salmon habitats.

Mass-market paperback books aren't produced locally, either (not enough sources of paper), so they're all extradimensional imports, or really old, or both (the ones in the crate in this story are probably both).

So the amateurish black-market barter we're witnessing here may be small-time, but the goods involved are more expensive than one might suppose at first glance.