This is really, really cool. And I love the home page! Being able to see results before signing up is great.

I'm not a potential customer right now, but the text on the pricing page "If you find a payment bug (incorrect charges, broken UI, etc), let me know and I'll give you the full version of PMAlerts for free, for life." would absolutely give me pause.

A simple addition if you're actually dealing with payment issues would be to add "I'll make sure your billing is straightened out ASAP - and never charge you more if you've been undercharged."

But ultimately, get your payment system functioning ASAP. I would not be comfortable putting my card info into a system that tells me ahead of time it might have bugs.