My usage would be very occasional, maybe once every two or three months, for an intense day or two. I'd have no problem forking over $50 to use it each time, bu

My usage would be very occasional, maybe once every two or three months, for an intense day or two. I'd have no problem forking over $50 to use it each time, but it would be very annoying to pay $10/month for months when I have no usage at all. See the paradox? I'd pay more, maybe $200/year, instead of $120, not to have to worry about getting billed forever for something I'm not using. If you could come up with some scheme that was usage-based rather than time-based, you might make more money in the long run. $5/screen? $50/project? I dunno. Maybe $100/year, upfront, non-recurring. That wouldn't be terrible. It wouldn't feel like time-based usage because the timeframe is so long. You might be able to learn something from the pricing experiences of the mockup tools like Balsamiq and Mockingbird.