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.
A popular category of ready-made spreadsheets mentioned earlier, is 'Spreadsheets for Actors'. 'Spreadsheets for Actors' includes sets of programmed spreadsheets that are especially designed for professionals in the entertainment industry, from Actors to Producers. The spreadsheets under 'Spreadsheets for Actors' range from facilitating the managing of budgets to keeping track of income emerging from many sources.
All of these things pull you away from the thing you really want to do...which is to build and sell great spreadsheets. The best thing to do is use Excelville.com since they have web developers and internet marketing specialists to help get exposure for your spreadsheet.
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.