One user at a time : In the instance where there are a number of people required to work on a spreadsheet, they can only access it when no-one else is working on it.
You may also want to track your current spending on one sheet with columns for different categories. Some individuals will list the budgeted amount in one column and then list the actual amount spent in the column next to it.
By opting for the competitive and performing "Spreadsheets for Small Business" and "Spreadsheets for Actors" ready-made spreadsheet packages in the detriment of time-consuming and difficult to use programmable spreadsheet generators, users can handle an extensive spectrum of business processes the quick and easy way.
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.