Most businesses need capital for sustain them while they are getting started. Basically, this means you need money to get started and keep the business going before your goods or services start selling. When you open the doors of a new business, you can't count on the money rolling in to cover whatever expenses you have. Capital is going to be in the form of your money or other peoples' money. As the previous posts suggest, you must have a business plan to know what those startup costs and ongoing expenses will be, no matter whose money you are using to get started.
If you are using your money to begin and sustain yourself for awhile, you maintain ownership and control of your business. However, if you use other peoples' money, they expect to have a return on their money, some control over the business, or sometimes both. This is something you must think about carefully, since you will then have obligations to others in some form.