1 Hourly rates for an outside bookkeeping service run $20-$50 an hour, depending on complexity and location. 2  Usually you can hire a trained, experienced bookkeeper on a contract basis for $30-$40 an hour, but there can be a minimum monthly charge of $100-$150 for small businesses that don't require a lot of work hours. An established Northern California retail store with 12 employees generates about 4-6 hours a week of bookkeeping work, or $480-$960 a month, plus $80 in monthly fees for a payroll service to issue paychecks and file payroll tax forms.