Enterprise Rent-a-Car - Enterprise Offers PTR Member Discounts. Enterprise Rent a Car is offering PTR members a discount off their lowest internet rate on car rentals in the United States. You can use this for your trip to Hilton Head Island for the Symposium, or for any other business trip, personal vacation, etc. To access the PTR rate for your next car rental, visit the site Enterprise has created specifically for PTR: Website