How do I sell a spreadsheet?
Updated
Why spreadsheets sell well
Spreadsheets sell well because they do a job the buyer was doing badly by hand, and the value is obvious within a minute of opening the file. Ship an Excel file and a Google Sheets copy, include example data and an instructions tab, lock the formula cells, and price on the hours it saves.
They also sell to businesses, who pay more and refund less than consumers.
Package it properly
Include example data so it does not open empty. Add an instructions tab. Lock the formula cells so nobody breaks it by accident.
Offer both an Excel file and a Google Sheets copy. Buyers are split roughly evenly and each group asks for theirs.
Price on the time it saves
A sheet that saves a contractor two hours a month is worth far more than most sellers charge for it.
Say the saving on the product page: "replaces the four hours a month you spend rebuilding this".
Protecting your work
Sheet protection stops accidents, not determined copying. Do not build the product around defence.
Updates and support are what keep buyers coming back to you rather than a leaked copy.