Depends on scale. If you're a decent salesperson you can operate out of your living room, keep overhead low and guarantee a profit... you just won't earn very much. When you build a team your marketing budget can get out of hand quickly if you want to generate any kind of real numbers, but it gives you a chance to build a book of business that should pay off later (if your purse can survive the ramp up). Many larger shops (15+) lose money on the front end and rely on the back end to keep them black. It's like any other business... the strong survive.