Sibling/birthparent search

I was born in Sioux City Iowa in 1973. My birthmom was also adopted. My birthparents had 2 other children who were removed from thier care in the early 1970's. On my adoption papers it says that my birth last name was martin.They also said that my birthparents were possibly married. I have been on the waiting list at the adoption agency for 3 years now. I am next to have my search done. It cost so much money to have them do it though(500.00)