I'm looking for a simple inexpensive (or free) spreadsheet that will work on Windows 10.
You can try Simple Spreadsheet in Windows 10 because even the developers says it's possible it might run in newer versions of Windows. Use the download link posted below to access the page. Secondly, there are other spreadsheet creation programs like OpenOffice or LibreOffice. There is no need to install all the modules, just the spreadsheet one.
Download Simple SpreadSheet: http://sss.sourceforge.net/