All vendors prefer US dollars. You need to take a taxi to the mall $5 each way. Do not pay the taxi drivers more. The Marriott is not very close to the mall. Can you change your reservations to the Lucerna? That is walking distance to OCC and the mall and is a much nicer hotel. The Marriott is in a not very nice neighborhood. The Lucerna is in the financial district with lots of restaurants within walking distance and even a Starbucks:) across the street. I have stayed at the Marriott once and the Lucerna three times. I wish someone would have told me this before I stayed at the Marriott, also go to Revolution Ave. Another $5.00 taxi trip with lots of souvenir shops. I have been to Tijuana 15 times now and drive in from my home in California so I have tons of experience there.