I’m in Canada, but much of the cost of adoption is the same.

• Legal fees to change the parentage (and sometimes the name) of anchild.
• Counselling for the birth parents.
• Travel costs for the birth parents.
• Background checks for the adoptive parents (legal, medical, and financial).
• Counselling/social work for the adoptive parents.
• Payment to the adoption agency for facilitating the whole process.

The only significant difference I know of in the US is that some ahencies are for-profit, and medical costs aren’t covered by unicersal healthcare, so have to be added on.