The full version of Akiko costs $15 USD (15 EUR). Once you've ordered the full version you will receive a keyfile which will unlock the Akiko demo version and also work with all future versions of Akiko. So you have to pay only once for Akiko and use it as long as you want.
The easiest way to order the full version of Akiko is to browse to the Akiko product page on RegNet which is http://www.reg.net/product.asp?ID=10270. RegNet allows you to pay with your credit card so that transactions are very quick and you will receive your keyfile within 24 hours after you've submitted the order form to RegNet.
If you don't have a credit card or you don't want to use it over the Internet, you can also order the full version of Akiko directly from me. To do this, print the order form and send it along with the money to me. Please note: I only accept cash, checks from Europe or postal money orders. I cannot accept checks from other countries because I would have to pay a fee to transfer it. Thanks for your understanding.