Simony is the sin of attempting to buy or sell an office of the Church or a sacrament. The word "simony" does indeed come from the name Simon, but not from the name Simon Peter. It comes from the name of Simon the magician, who had heard the preaching of Philip in Samaria and had accepted baptism.
In Acts 8:9-24 we find the account of this Simon, who offered money to Peter in exchange for the power to lay hands on people to confer the Holy Spirit. From Peter came an immediate and sharp rebuke. Ever since, the notion of buying an office of the Church or of buying grace has been referred to as simony.