"90 days before we ask for a credit card, then less than $40 per year after that. Try us for 3 months let us show you how to save time, money and hassle for less than the cost of a family meal per year"

Just a thought to throw out there.

The issue with most subscription web services is that people who foresee using it a couple of times a month end up not signing up. Which is all lost revenue. LastPass charges​ $1 per month. I think that's the magic number for casual users. They may only use this once every month or two. But $12 can easily be forgotten / justified.

Don't think. Test.

People on HN might be cheapskates but your target might be willing to whip out their wallet sooner.