A working man would need a quart of wheat (= approximately half a kilo) per day to sustain his own body. Since a denarius was the daily wage for the average labourer (see Matthew 20:2), that means that a worker would not be able to get enough income to feed his family, let alone provide shelter and clothing.
6 And I heard what seemed to be a voice in the midst of the four living creatures, saying, “A quart of wheat for a denarius, and three quarts of barley for a denarius, and do not harm the oil and wine!”