If you teach Personal Finance, this is a great tool for helping students develop a "pay yourself first" budgeting philosophy. It also can be used to teach the use of spreadsheets and mathematical formulas, as well as math concepts like percentages.
Students start by entering their projected monthly salary. Then they allocate, by percentage, how much will go to various types of investment and savings funds. They finish by entering their expected monthly costs. The result is the "guilt-free spending" they can safely spend this month on anything they want. This demonstrates responsible budgeting and spending, and sets them up for future financial success.
This file can be uploaded to Google Drive and converted to Google Sheets and will still function properly, though some small changes in font or color may occur.