Fees and Turkey Visa Validity

Though there are some controversies regarding the visa fee structure as levied by the Turkish government, the current fees charged for entry visas at border gates can vary by as much as $45 (or 35 Euros) depending on nationality.

Canadian and Norwegian citizens currently pay the most to enter Turkey at point of entry - paying 60$ for a 90 day entry visa. Americans pay $20, as do the Australians and the Russians. Buying a visa at a Turkish consulate before you travel will cost you more - American passport holders will pay $45 for a single-entry visa and $150 for a multiple-entry visa. British ordinary passport holders pay £10 in sterling at the border, or can obtain a six-month entry visa for £66 (£207 for one year) or a multiple-entry visa for up to five years for £207 from the Consulate General for the Republic of Turkey in London.

Citizens from Greece, France, Germany, New Zealand, Japan, Denmark and Chile among others do not have to pay at all - they do not need a visa to enjoy a 90 day stay in Turkey. Other nationalities must apply to their nearest Turkish consulate for permission to enter the country. As such, they cannot buy a visa from their port of entry. Other nationalities still can buy entry visas for less than 90 days.

Useful websites
Please note that visa requirements and fees are prone to change - you must speak to your holiday representative or Turkish consulate BEFORE you travel to confirm your personal visa situation.
Turkish border fees for 2009
Country by country visa requirements for Turkey

Generally, a visa should be used within a maximum period of twelve months from the date of its issue unless otherwise stated. Otherwise it may expire.

So if you are planning to make a trip to Turkey, do follow the procedure for obtaining a visa from the Turkish consulate or otherwise carry the exact amount of cash so that you can purchase it from the counter at the airport in Turkey. Do follow the legalities to avoid any trouble.