This first picture is at the U.S. Mexico border. In the town of Progreso, Texas, there is a crossing into Nuevo Progreso, Tamaulipas. I had originally intended to go to Matamoros from Brownsville, but found some not so great things about the city online.
When you walk in to Nuevo Progreso, you are hounded by people selling pharmaceutical drugs. I wasn't looking for any, but I did find a bottle of tequila that was $35 in the states for $10 and a delicious pineapple for $1!
This is picture of one of the markets.