I called about 3 different vets in the city and they all told me that I need to go to emergency unit for oxytocin shot!!!

IT costs about $500+ !!! Why is it so expensive? My vet told me to wait since little pieces of placenta are coming out little at a time.... I don't know what to do... Is it really bad to wait for it to come out naturally?
By the way, puppies are so cute and funny... some of them are sucking at each other's ears and paws thinking its mommy's nipples... LOL