Both domestically and abroad, there is a strong preference for girls, probably due to the perception that girls are "easier." Even with international adoptions from countries like China or India where there is a strong cultural preference for sons, orphanages are still overrun by boys because the demand for girls into adoption is so high. There's a perception among foreigners that those orphanages are full to the brim with girls due to parents abandoning daughters at birth -- but nope. Even with international adoption, if you want a healthy baby or toddler girl, you'll probably be waiting longer than parents who want (or are willing to take) a boy.
Basically, if you want the costliest, slowest adoption with a high risk of failure due to birth mother changing her mind, set your sights on a healthy Caucasian newborn girl. You'll be paying $25,000-35,000 AT LEAST and likely be waiting for years. If you want a the quickest adoption at low or no cost, then adopt an older black boy, a child with special needs, or a sibling set from foster care.