Web app used to track donations based on how much you tell it you make, how much you tell it you've already given, and what percentage you tell it you'd like to give.
- Table for income - supply it with date, amount, recipient name (like for couples), notes
- Table for donation payments - supply it with date, amount, where it's going, maybe notes
- Table for recurring donations - supply it with a way to link to individual donation payments, plus amount, recurrence, where it's going, notes.
- Options - what percentage you'd like to give, maybe storing the names of commonly occurring things, time periods to track (ie track your monthly donations)
- Add/edit/delete an income transaction
- Add/edit/delete an individual donation (ie give to a disaster relief that doesn't repeat automatically)
- Confirm a recurring thing actually happened (ie you actually did give money to your church this month)
- Update percentage option, any other options
- Forms above
- How much you've already given this time period in total and percentage of tracked income
- How much you have left to give this time period if you want to meet your goal (can be negative if you go over)
I'm not convinced any of this data needs to be stored on a server. Maybe if it's somehow anonymized? But I think storing it locally on the user's device (with HTML5 or whatever) is perhaps better than dealing with the privacy implications of storing what percentage people want to give away, what amounts they say they actually receive, and what amounts they say they actually give away.
While storing the data locally does make it volatile in its own way, to device loss or data expiration or any number of things, it seems worthwhile. Maybe remind users to export it from time to time if they want to save it somewhere.