How much does it cost to file the DS-160?

This is a trick question. It costs $0 to file the DS-160. If you have been charged otherwise, you were scammed. The DS-160 can be filled out for free on this website: https://ceac.state.gov/GenNIV/Default.aspx

The visa fee does cost money (which varies depending on the type of visa you are applying for). It is paid when booking the visa appointment. See this article for an explanation of where to book and pay for your visa appointment.