Castanhas do Pará (Brazil nuts) are not that expensive in Brazil are they? I'm seeing R$50/kg on an ecommerce site, that's like like $5/lb. I'll try to get a better price quote tomorrow. You can't have too many of them anyway, it can cause quite a movement of the bowels.

Caju nuts I'm assuming are expensive because they are mostly exported. It's probably the same as arabica coffee in Colombia, it's too good to consume domestically.

Caju fruit you're probably right, does not travel well. Same as açaí, that won't go far without refrigeration or freezing.