Hi, I'd like to use Formfacade for a non-profit mental health program. How long is the free trial? And how is pricing set up afterwards - is there a way we can pay different monthly totals based on how many uses we had during that month? For our purpose, the number of uses will vary over the months. For example, months 1 and 2 will total 223 uses, then months 3-5 will only have a handful of uses, then over 200 again in months 6/7.