This is by no means limited to the NBOME (or the NBME). It's not even a well-kept secret. The key to making money in medicine is no longer in actually taking care of patients. It is getting involved in medical education and making yourself indispensible, or close to it.
If you think the fees for COMLEX and USMLE are bad, wait until you take your board exams. Specialty boards are even worse. And don't forget recertification fees. You could try to go without board certification but good luck getting on any insurance plans or getting hospital privileges in any reputable institution. You also need to get licensed in your state to practice, which needs to be renewed every few years (more $$).
The title of this thread should change to "How to rake in money from doctors"
Note that these boards are all ABMS, not AOA
American Board of Internal Medicine
http://www.abim.org/exam/cert-cost.aspx
Internal Medicine Certification Exam: $1,280
Subspecialty Certification Exams: $2,060 (except for Advanced Heart Failure & Transplant Cardiology, Transplant Hepatology, Cardiovascular Disease, Interventional Cardiology, and Clinical Cardiac Electrophysiology)
Subspecialty Certification Exam in Cardiovascular Disease: $2,195
Subspecialty Certification Exams: $2,650 for Advanced Heart Failure & Transplant Cardiology, Transplant Hepatology, Interventional Cardiology, and Clinical Cardiac Electrophysiology
Late Registration fee for 2009 Certification Exams (non-refundable): $400
American Board of Pediatrics
https://www.abp.org/ABPWebStatic/#murl%3D%2FABPWebStatic%2FgenPedCertification.html%26surl%3Dhttps%3A%2F%2Fwww.abp.org%2Fabpwebsite%2Fcertinfo%2Fgenpeds%2Fgpdatefee2010.htm%3Fsection%3Dcert
2010 Calendar Year Fees
Regular Registration
$2,030.00
Late Registration
$2,335.00
Late Fee
$305.00
American Board of Emergency Medicine
http://www.abem.org/PUBLIC/portal/alias__Rainbow/lang__en-US/tabID__0/DesktopDefault.aspx
Initial Certification Application - $390 (early), $535, $1200 (late)
Qualifying Examination Fee - $920, $1880 (late)
Fall Oral Certification Fee - $1140, $1410 (late)
American Board of Family Medicine
https://www.theabfm.org/cert/2010CERTCandInfoBook.pdf
Application Registration - $1250
Late Registration (ranges from $1400-$1850)
American Board of Surgery
http://home.absurgery.org/default.jsp?examfees
General Surgery
Qualifying Exam - $300 application fee ($500 late fee) + $700 exam fee
Certifying Exam - $900 exam fee
American Board of Anesthesiology
http://www.theaba.org/home/fees
Application for Certification - $850 (late fees range from $1100-$1700)
Part 1 Exam Fee - $525, Part 2 Exam Fee - $1950
American Board of Pathology
http://www.abpath.org/Fees.htm
Anatomic Pathology only - $1800
Clinical Pathology only - $1800
Combined anatomic and clinical - $2200