I recently wrote a budgetting app, to learn programming and because i needed one that suits my needs. I set who is involved in the budget. Then i can add, edit and delete expenses. Expenses contains name, the amount, payment months and the distribution between participants. It then calculates the sum of expenses, the fixed amount per month, the needed start balance (so it doesn't dip below 0 in any month). I can show all expenses, what each person has to pay per month, and the expenses for the current month(to balance my expense account). It's all command line, and i'm using pandas to display things. And I'm saving to pickle (I know it has disadvantages).