I cannot help you answering your question, because there are different types of Passport/VISA you are applying for and varies fees to pay for whether you are single, married, engaged/to-be married, and/or have children/family that requires to apply separate Passport/VISA application per person.
You should make aware the fact that all spouse, family/relative, children and babies if you plan them to travel with you that are required to apply for passport/VISA each person per application separately. You also pay separate fees for each Passport/VISA application for your spouse, family/relative, children/baby individually. All of them are required to be presented for Passport/VISA interview appointment in order to get fingerprinting and/or biometrics if grant passport/visa.
Check out existing topic you will find below:
How can someone living abroad obtain the new E-passport?http://www.nairaland.com/nigeria/topic-93255.0.htmlThe following official US Passport/VISA sites at below:If you are US resident (fully US citizenship) to find where to apply for a Passport nationwide, see this link of the Passport Acceptance Facility Search Page at below:
http://iafdb.travel.state.gov/How to apply in person for a Passport link at below:
http://travel.state.gov/passport/get/first/first_830.htmlHow to get a VISA for immigrants (non-US citizens) link at below:
http://travel.state.gov/visa/immigrants/info/info_1339.htmlYou need to know which type of VISA you want to apply for.The following official Nigeria Passport/VISA site from the US travel's external link at below:If you are Nigeria resident (fully Nigeria citizenship) to find where to apply for a Passport/VISA, see this link of the Nigeria Embassy contact information at below:
http://www.immigration.gov.ng/index2.htm