I asked a close (American) friend of mine who lives in Ankara the question, two weeks ago. He said it was $45. The US State Department's website also says this amount:

http://travel.state.gov/foreignentryreqs.html#t

TURKEY - *Passport and visa required. Visas can be obtained at Turkish border crossing points for tourist/business visits up to 3 months or through a Turkish consular office in the U.S. Visa requires a letter stating purpose of trip and $45 fee (cash or money order only). Visa must be obtained in advance for visits lasting longer stays, and for study, research, or employment purposes. For further information, contact the Consular Office of the Embassy of the Republic of Turkey, 2525 Massachusetts Ave., N.W., Washington, D.C. 20008 (202/612-6740/41) or nearest Consulate: CA (323/937-0118), IL (312/263-0644), NY (212/949-0160) or TX (713/622-5849).

[This message has been edited by Craig6z (edited 03-17-2003).]