Watch out for some banner tow companies
Some banner tow companys make you pay for your own training. They will tell you that you are paying for required FAA flight training and an instructor's sign off, when actually there is no requirement.
They may charge you $1000-$2000 so that they don't have to pay to train their own employees.
This is just another way that some aviation employers try to screw their employees. A good company that values it's employees will cover the expense of training. They are investing in you as a professional.