There’s a price war raging in the grocery aisle—but the people who actually grow and gather our food may be the battle’s true losers. Meet the produce pickers of Texas’s Rio Grande Valley, whose penny-per-bunch harvest helps stock your pantry for less.

Our food is cheap—by some measures, cheaper than it’s ever been. Americans now spend less than 10% of their disposable income on what they eat. When researchers first began tracking this figure some 90 years ago, it was closer to 25%.

But the inexpensive supermarket fare that consumers now expect doesn’t come without a hidden human cost. To see, firsthand, the true price of keeping those shelves stocked, Fortune traveled down to the Rio Grande Valley—among the best areas in the country for growing food crops, and one President Trump put in the spotlight last week when he visited the region to make his case for the border wall.