Oil prices have fallen nearly 60 percent since June, but it's not the only commodity that's dropping in value. Grains, metals and other bulk products have been plunging too.
Since February 2011, copper has fallen from $4.50 a pound to $2.53; corn fell from $7.50 a bushel to $3.88. The changes have a put a squeeze on farmers and miners, but so far they haven't really trickled down to consumers.
NPR's Marilyn Geewax joins Here & Now's Robin Young with details.
This segment aired on February 12, 2015.