Up to this year visitors to Turkey obtained a 3 month visa to enter the country by enclosing a 10 note in their passport when entering the country. The rules have changed now and I have copied here the official announcement and we are now in the transition period. What I am trying to draw to Wiki members attention is the fact that when you Google evisa there are a large number of unofficial sites that obtain evisas for you but charge large commissions for the service. Last night a friend of mine went on a site and filled all his details in and payed at the end and was charged 55 instead of the $20 that is the correct charge
19/02/2014 - Announcement[b][/b][/u]
[u]Visa Applications at Points of Entry to the Republic of Turkey as of 11 April 2014 and Measures to be Taken During the Transitional Period

In accordance with the new Law on Foreigners, the practice of obtaining visas upon arrival to points of entry to Turkey will begin to come to an end as of 11 April 2014. However, border authorities will maintain existing procedures for a certain transitional period, to include the 2014 tourism season.

Visas for touristic or business purposes can be obtained via the new Electronic Visa Application System (www.evisa.gov.tr). This system, which was launched in 2013, allows intending visitors to obtain their e-Visas in approximately three minutes online.
There are numerous web sites which claim to assist users in receiving Turkish e-Visas in return of a service charge. These websites are not endorsed by or associated with the Turkish government. Therefore, we cannot be held responsible for any misuse of information or failure of service on their side.

The above paragraph warning of this dodgy practice is copied from the official Turkish website and contains the only URL of the only official website from where evisas may be obtained.