The Federal Consumer Protection Act mandates that there can be no more than 60 % total wage garnishment if not in arrears for child support and 65 % if in arrears for child support.
The order of priority for garnishment is as follows:
Child Support second
Other garnishment for attorneys fees and debts last
Therefore if paying child support takes 65 % of your income, then $ 0 can be garnished for other debts.
The federal law is discussed here.