If I recall correctly there are strict limitations on counting your car, cell phone and rent as business expenses and they require extensive amounts of documentation. I don't know how much they enforce these days since everyone and their brother is hustling a pyramid scheme business but I would research it first. Getting audited without reliable mileage logs, phone records in your favor and a measurable separation between your personal living space and your work area (like a door) could result in being stuck with a tax bill for back taxes.