We rented from Budget, Ocean Ave. location, when we sailed into San Pedro on our Feb cruise this year and returned the car at the Ontario airport location. You will have to take a taxi to or from San Pedro as the location is not walking distance. But it was easy to do and not much of a problem at all.
You can do the reverse as well. Drop off a one way at the Ocean Ave. Budget location and they'll get a taxi for you to the pier.
The taxi cost was about 15.00 each way.