son un poco caros

they are a little expensive

→ ser
phrase Rare #47,129
they are a little expensive Caros agrees with a masculine plural noun or group.
SP: Los zapatos son un poco caros.
EN: The shoes are a little expensive.

Los ingredientes necesarios para esta receta son un poco caros.

The ingredients needed for this recipe are a bit expensive.

Y los violetas, aunque son un poco caros.

And the purple ones, although they’re a little expensive.

Esos son un poco caros.

Those are a bit expensive.

— Un Taxista (2017)

Los ingredientes para esta receta son un poco caros.

The ingredients for this recipe are a bit expensive.