Great news. Just please don't make it free. Make it good, and price it at $5 at least.
Out of curiosity, why do you recommend charging?
I'm all for earning revenue from my applications but in my experience the ad-based or donation models have been more lucrative.
Professional applications for banks and financial services are usually free - look at the apps for Lloyds, Barclays, American Express, Bloomberg etc.
Using a freemium or ad-supported model cheapens the user experience and reduces the professionalism of the app. Could you imagine checking out your current account balance on your app, only to have a banner ad for payday loans flashing across the bottom of your screen? Blerg - cheap and nasty.
If you have to charge, I'd suggest somewhere in the region of £1.59/$2.59 - but make it worth it. But, this should really be funded by the group that stands to benefit the most - namely, Havelock. They have just paid the developer 1 BTC, which is a good starting point.
I'd estimate a good app for a flourishing new financial service should net the author in the region of $50,000-$100,000 (I say this because the app for telling you where to stand on the London underground for the quickest exit earned its developer £50,000 - $80,000). A very worthwhile reward for contributing to our growing little ecosystem here.
