USCIS Immigrant Visa Fee
Effective February 1, 2013, all individuals issued immigrant visas overseas must pay a US$ 165.00 USCIS Immigrant Fee before traveling to the United States.
The only exemptions to this fee are children under the IR-2 category who will qualify for the Child Citizenship Act or children adopted under the Orphan (IR-3s/IR-4s) or Hague processess (IH-3s/IH-4s), Iraqi or Afghan special immigrants who were employed by the U.S. Government, returning residents (SB-1s), and those issued K visas.
The below USCIS website has more details on the new fee, including how to pay the fee and contact information for USCIS, if there are further questions: