Yes, this option is available from Budget Car Rental. Details are outlined on this page of their official website. In short, you will need to complete the first steps of the booking process (entering your personal information, marking your location, and picking the dates), select the vehicle you wish to use, review the total costs - and make sure that the form lists unlimited mileage as an included option. Once this is sorted, you need to make a payment, and the process is complete.