At present, some of the most requested types of spreadsheet packages in the market are: 'Spreadsheets for Small Businesses' and a subset of that: 'Spreadsheets for Actors'.
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.
Inconsistent data : This becomes most apparent when trying to find a particular record or cell, based on the contents. If a space is incorrectly added in the wrong place, the search or filter fails.
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