As a rule of thumb, I've observed that most businesses charge between 2-4 times as much as the employee is paid for hourly work. So without more information on overhead etc, $41.25 to $82.5 per hour seems fair in your case.
However, it can be a lot worse than that in non-tech locations. Where I live, you often see $60-100 hourly rates in shops where employees are only paid $15/hr. Each business you see on the street supports roughly 1 family, so they might use turnover or other techniques to stay in business for the long term while paying wages that are below the going rate. I'm wary of jobs now that convey a feeling of owing something to the employer, as this correlates with subpar pay. The best jobs that I've had have felt very mutually beneficial to employer and employee.
However, it can be a lot worse than that in non-tech locations. Where I live, you often see $60-100 hourly rates in shops where employees are only paid $15/hr. Each business you see on the street supports roughly 1 family, so they might use turnover or other techniques to stay in business for the long term while paying wages that are below the going rate. I'm wary of jobs now that convey a feeling of owing something to the employer, as this correlates with subpar pay. The best jobs that I've had have felt very mutually beneficial to employer and employee.