You should n9t have to pay out if you document the reviews sith the employee, make it clear what they need to do, the first warning should give clear goals, the second warning should give a timeline to correction, and the third warning accompanies termination. Usually a justified termination does not pay out unemployment. I could be wrong on this, consult your lawyer.
Find out how much money a tax proffesional wants to be paid to help you. Maybe get three estimates.
Turn this into a yearly cost, then divide that cost by the number of units you will sell in a year.
Raise your price per unit by double this cost.