I will be traveling to Turkey in Oct. I know I need a visa and that I can purchase one when I arrive. Do I need any paperwork, extra photos? Also, do I just tell them I need to purchase a visa when I go through passport control? thanks in advance for the help.
Just your money, in US Dollars (Euros would work as well I believe) is needed. Depending on the point of entry, it may require going to a separate window from passport control.
If you arrive at the Istanbul airport, the visa window is just before the passport control windows. You need to get your visa stamp BEFORE getting into the passport control line (the officer will put the stamp into your passport). If you didn't get your stamp first, there is a gate through which you need to exit, get your stamp, then re-enter the passport line at the end.
And to add to the above posts and in answer to your other question, you do not need a photo or any other documentation, just the money and your passport. The visa is just a stamp put in your passport.