Using icons and circles to represent income and expenditure, as well as colours to show how good/bad a user's finances are. The idea is that people can see where their biggest expenditures are at a glance, without having to trawl through lots of figures, whilst also being ideal for people who struggle to understand how much an amount is (e.g. £10) compared to their income.
The colour of the app would change according to how well the person is doing regarding their spending versus their income (red being bad, green being good). The bigger the circle (and also the stronger the opaqueness), the greater the expenditure is compared to income.