The plans offered by Adobe at the Creative Cloud Plans page at https://creative.adobe.com/plans do not offer an option to pay the year all at once.
But it is cheaper monthly if you choose the Annual plan versus the Month-to-Month plan. The catch is that the Annual plan is a contract and that if you cancel before the year is finished you are charge 50% of the remaining contract.
Amazon does offer redemption cards that let you pay in 3 month or 1 year increments all at once.