Ultrasound

My doctors office doesn't do ultrasounds there as they don't have the equipment. They send you to a nearby hospital to have it done (the same one I will be delivering at). My first ultrasound at 20 weeks is in a week and I've been trying to call and find out how much it's gonna cost (I don't have insurance) but of course no one will answer the phone. Does anyone know around how much a hospital charges for an ultrasound in case I can't get ahold of anyone between now and then?