I'm trying to get another idea I have into a startup, but I haven't been able to get that off the ground.
For a while I was doing cheaper time-limited licenses, like $1 for 6 months, $2 for 1 year, etc and $10 for lifetime.
Best source of customers is from free users. I started the app as free until version 3.0 when I switched to freemium. Sales have been fairly consistent each month for years, with spikes when a blog picks it up.
http://www.delibarapp.com/ http://www.potionfactory.com/thehitlist/ http://culturedcode.com/things/ http://sophiestication.com/coversutra/
If a new website isn't possible or you want some other ideas here are a bunch: 1. Mess with your pricing a bit I was comfortable paying $7 would i have preferred $5 and would not buy at $10 which is where it is now. I think with some A/B testing you could find a better price point.
2. Your checkout makes me want to cry So as a potential customer i click upgrade to pro and get taken to this http://screensnapr.com/e/Rrn828.png . Why has the price double? Why are you trying to up sell me stuff? Why am i on an external website that i have never heard of before? Maybe spend some time/money setting up a more user friendly checkout system that wont cause potential customers to give up half way through the sale.
3. On your website sell benefits rather than features, to get you started "It a bloody million times more accurate than the inbuilt one"
Marketing Ideas (preferable once you have fixed your website) 1. Make a battery app for the iphone (there are tons of free ones) and you would be a small fish in a big market but if people do get your app you can cross sell plus if you get mentioned on any blogs you can try and get them to link to BatteryBar as well.
2. Are you actively talking to blogs and app review sites or are you hoping they stumble across you?
Hopefully that helps, its a mess of ideas but and comments but hopefully that is useful. If you need some more input ill try, just send me a message on twitter @nico_kunz