In my web app I allow users to create payment plans for their subscribers. I currently only support one option: a monthly charge. I am working on adding multiple options, including one-time payments.
My question is how would you present this to the user? Here is my current idea. Users can 'Add a Plan', and choose 1-, 3, 6-, 12-month, or one-time payments from the drop down. The issue with this is that I want to prevent duplicate interval selections, and I'm having a hard time doing that with jQuery.
So, do you think there is a better way? I was considering changing the drop-downs to number fields, which would make duplicate detection easier, but then how does the user indicate a one-time payment option? A check box next to the interval field?
Any ideas on how I can make this clear and easy for the user? Thanks!