Are towing rates regulated?
For non-consent tows, such as police-ordered or private-property tows, many states and cities set maximum fees for hook-up, mileage and storage. Tows the owner requests are usually priced freely, but the price should be agreed first. Check the rules where you operate.
How do motor clubs and insurers pay?
Usually against their own dispatch or claim number at their agreed rates. Put that number on the invoice, and bill the vehicle owner only for anything outside the cover, such as extra miles.
When does storage start?
Commonly after the first 24 hours, charged per calendar day or per 24-hour period. State which in your terms and show the dates on the invoice.