$187-$1,147 (in 2012). The range is because an employer's tax rate is based on its claims history over a period of three years. The lowest rate is 2.2%; the highest rate is 13.5%. Employers are only taxed on each employees first $8,500 in wages. Overall rates are likely to be lowered in 2013. Even at the very highest end, the total tax per week is under $25.
I have represented employees at several recent unemployment hearings. It always surprises me how personally some employers take claims for uninsurance benefits. Most such claims have little affect on the employer's experience rating and its bottom line.