100 PROJECT MANAGEMENT FOR SMALL BUSINESS + activities. Having a great project cost estimate is fine, but if the project is plagued with errors, someone is going to have to pay for the cost of those errors. Creating Project Cost Estimates Think about the type of project work you do for others. What are some typical expenses in your project that you have to pay for in order to get the work done? For instance, do you have to buy materials, rent equipment, hire contractors, or file permits? A question I like to ask business owners when I consult is sim- ply, "How do you know how much a project will cost?" Sometimes the owner has a stack of invoices, worksheets, and records to show how he's created cost estimates for previous