We're not fans of paying several dollars per month for a task management service either.
Do 14-30 day free to paying trials work? That's out #1 plan for now.
We find the $9.99/year price point attractive, with $0.99/month it's not worth it and we'd rather give the service away for free. There are micro-payment processors out there but we're looking at overall cost and strategy when looking at pricing plans/feature set we'd like to make available at each price level, and really love the simplicity of Stripe for payments.