On my Contextures site you can download my free pivot table add-in, PivotPower. So far, I haven’t created an Excel product for sale, but a few of my Excel colleagues have.
One of the challenges is in setting a price for the software. How do you decide what to charge?
To help you through the process, you can download a free pdf file of the book Don’t Just Roll the Dice, by Neil Davidson, of Red Gate Software. If you prefer a physical copy of the book, you can buy it on Amazon.