What was Peter's response then?
In verse 11 they LEFT EVERYTHING AND FOLLOWED JESUS.
Immediately following that account, we discover that Jesus cleans an unclean leper, and forgives the sins of a paralyzed man. Then, seemingly random, He notices a tax collector (dubbed a "sinner" by the Pharisees) and says, "Follow Me." What was Levi's response? He LEFT EVERYTHING AND FOLLOWED JESUS.
Jesus then answers the grumbling of those who objected to the type of people who were coming to follow Him: "I have not come to call the righteous but sinners to repentance."
Whether it was an overconfident fisherman, an unclean leper, a helpless paralytic, or a despised tax collector--the ground was level for all of them: a sinner in need of a Savior.
Not only was the ground level when coming to Jesus, the cost of following Jesus was the same as well.
Whether leaving a fishing business or a lucrative taxing business: both Peter and Levi "left everything" in order to follow Jesus.