Just a thought - if you provide an interface just after "scanning" the bill where you can easily tap line items to get a total it would make splitting a bill much easier.

You might also provide a way of tapping the number of people who shared the meal to split the bill (quick and painless divide) or an easy way to calculate a tip.

Finally, being able to tag line items then and there could be useful - say you purchase some stuff from the supermarket and a couple of those items are business while the rest are personal.

Looks like a beautifully simple first step. Well done.