I agree with WCollins.
Many, many people said how delighted they were with the original Notamplot. and presumably made their voluntary charity donation when they downloaded it, so effectively paid something to use it.
The deal with AvBrief sounds great! Free for local bimblers who, perhaps fly relatively few hours to spread their fixed costs over; subscription for the more adventurous, delivering more added value for those who need it and for whom saving the last penny is not their first priority.
Well done Ian and AvBrief.
AA.