OctoEverywhere doesn't currently support a one-time payment for Supporter Perks. Our service costs us funds to run each month, and we use the Supporter Perks income to cover the hosting and development costs.
However, a good alternative might be purchasing a year's worth of Supporter Perks and then canceling immediately. You will then get Supporter Perks for the entire year you paid for but will not be atomically charged the following year. You can repeat this process on-demand as often as you like!
If you have any questions, contact us via our support system!