If you wish to contribute to the Ellopos / Elpenor Project, you can choose between 4 voluntary subscriptions. All of them are annual and all are managed safely by PayPal. You may renew your donation after a year, only if you want at that time (you will be asked).

      If for any reason you'd like to avoid the subscription scheme, you have also the option to donate whatever amount just once.

Reference address : http://www.ellopos.net/elpenor/subscriptions.asp