The difference between the different types of wages stems from the type of work and their payment modes.
Explanation:
Hourly wages: these wages are handed out according to the amount of work done in term of hours which means that there is a fixed rate for every hour of work.
Salary wages are given by the end of the month in that the m=number of days that a person will work, for a fixed amount of hours is fixed and the salary for the whole month's work is paid together.
Contract wage: this wage is completely dependent upon a pre decided amount for a predicted work and varies on the deal that the contractor and contracted sign.
Commission mode depends on the amount of effective work done. For example, in sales the salary would depend on number of items sold.
