Yes, Lan is full of insane sayings. IMO he was saying that the worth of a thing is determined by how much it costs to obtain it. I'm not quite sure value works that way.

It's almost like that example that Aviendha provided concerning how many clans would die over a puddle of water in the Waste, but in the Westlands and much of the rest of the world, water falls from the sky and is available so freely for drinking and other purposes that to a Wetlander, the value is much lower.