Mexico is a country of changarros (chan-GAHR-raw). A changarro is a micro business that barely gives its owner subsistence earnings. Changarros are typically located in improvised spots (the sidewalk, one's house garage, the median of an avenue) and almost always lack any permit to operate.
In the image, a changarro owner mocks himself with a sign that reads "Y todo por no estudiar" which could be translated as "This is what I do for dropping out of school". Working at this sort of micro businesses is in no way seen as success.