Selling spreadsheets helps you to build a catalog of spreadsheets that you can take with you and use in various areas of your life. Spreadsheets built for sale are usually built for flexibility and would be customizable to your life, or job, or new life, or new job.
You'll need to include more than a basic level of development and calculation in your spreadsheet. There are lots of free spreadsheets on the web. Most of which are very simple and easy to build. People aren't going to buy a spreadsheet that they can get for free. Take yours to the next level by adding all the value you can imagine. Then research on how you can offer a little bit more on the development and functionality side.
You could make money doing something you love (or like [or maybe not so much but just really good at]). It's great to see a spreadsheet come together, and usually a lot better than what you originally envisioned. Especially when the dang thing works.
A popular category of ready-made spreadsheets mentioned earlier, is 'Spreadsheets for Actors'. 'Spreadsheets for Actors' includes sets of programmed spreadsheets that are especially designed for professionals in the entertainment industry, from Actors to Producers. The spreadsheets under 'Spreadsheets for Actors' range from facilitating the managing of budgets to keeping track of income emerging from many sources.
uses of spreadsheet
excel inventory templates
excel spreadsheet examples