On the U.S. side, the Greyhound Bus Terminal is located on the east side of Interstate 5, about 100 feet from the Mexican border. The parking lot for these buses is literally the southernmost piece of real estate in these parts before the border fence. On the Mexican side the bus station is located just in from the border, on the walk towards Avenida Revolucion.
TAXI Taxis are available on both sides of the fence at the Tijuana border.
Prices are somewhat consistant, but can vary a bit from cab to cab depending on the variables. Get a price from the driver before you get in the taxi.