Where do I go if my child has no health insurance, and his doctor wishes payment at the time of visit but I have none?

Several choices. Any emergency room is mandated to see your child whether or not you can pay at the time. There are agencies in most cities with social workers who can advise you on mechanisms for having the child seen. Perhaps if you discuss this with the doctor you can arrange other circumstances than cash.
Uninsured 's healthc. If u have no isnurance and are unable to pay 4 ur child's healthcare, u can go 2 the county clinics. They will help u to even get enrolled in the state medicaid insurance program.