The whole sheet. Try anything.
This works exactly like your own copy, filled with a made-up year. Type a purchase into the Log, tick it paid, pick a month on the Dashboard, or rename a category and change your payday in Settings.
Your changes stay in this browser only. Undo works, and Start over brings the sample year back.
Tip: double-click a date for a calendar, right-click a row to insert or delete it, and paste rows straight from another sheet. Your own copy is a full Google Sheet, so everything else Sheets does (formatting, extra tabs, your own formulas, sharing) works there too.
Your own copy works exactly like this.
It lives in your Google Drive, starts empty with your own categories and paydays, and works in Google Sheets on a computer or in the free Google Sheets app. One payment, no subscription.
Want to see it inside Google Sheets first? Open the view-only sample sheet.