This app is based on the good old fashion way of budgeting and saving by putting money in envelopes each pay period - and there are 30 envelopes available.
The amount you put in the Cost boxes is like putting that money every pay period in an envelope that has the name of the ‘bill’ on it - and the money in that envelope is used only for that bill/cost and nothing else.
Example: if something costs $1000 a year, and you get paid weekly, divide $1000 by 52 and put $20 in an envelope; if you get paid every two weeks, divide by 26 ($40 in envelope), if you get paid monthly the divide by 12 and put $83.33 in the envelope.
Each envelope will have more and more money in them each pay period, and if you never spend more than the number in ‘Disposable Income’ per pay period, you will have enough money in the bank (‘envelops’) to pay for bills as you get them.