Economic access to sufficient and nutritious food is a necessary (but not sufficient) condition for food security. We present FoodpriceR, an R package for assessing the affordability of three least-cost diets: the Cost of Caloric Adequacy (CoCA), the Cost of Nutrient Adequacy (CoNA), and the Cost of a Recommended Diet (CoRD), which adheres to national FBDGs. Using linear programming, the package identifies limiting nutrients and computes shadow price elasticities, providing policy-relevant evidence. By comparing representative household diet costs with observed food expenditures, FoodpriceR identifies households unable to afford each diet and the affordability gap across income levels. The package contributes locally by providing preprocessed data to facilitate affordability analyses for urban households in Colombia, and globally by remaining adaptable to diverse case studies, offering a flexible, accessible, and reproducible framework in R to assess the affordability of least-cost diets.