If you don't have a printer, you can go to your local library or Internet cafe and run it off. If you are booking through a Travel Agent they will do it for you. It's $20.00 around £11.00 for an online Visa.
It's £20.00 each at Dalaman. We arrived at Dalaman in May and the man from the couple in front of us had no Visa. He wandered out of the queue to find a booth to get one, he came back and said there was no booth.
On reaching the desk. The guy told the Customs man he had no Visa. The Customs Guy made a phone call and then told the couple to go to the back of the queue and wait. The queue was very long. The guy tried to argue but the man waved him away and called us forward. Moral of the story, get a visa before you leave.