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.
The templates designed to use for saving calculations varies according to the saving calculations made depending on the types of calculations to be made. These spreadsheets make the calculations and the data entry easier than doing it by any other format.
You'll need to develop good marketing material. Things like demo videos, which you can find plenty examples on YouTube, screenshots, and keyword rich descriptive text help people find your spreadsheet and communicate the value that sets yours a level above the rest. Excelville.com actually allows you to upload your spreadsheet with all of this marketing material in an easily searchable and user friendly website.
Today, there are a large number of options to choose from. The downside to upsizing your spreadsheet to a database system is that databases require fairly in-depth knowledge, especially with regard to extracting data in queries, form construction and reporting.
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