For future reference, to get to the Greyhound station is somewhat convoluted. Although it is about a mile and a half south of Amtrak at LA Union Station there is no direct bus to get there. The cheapest way would be to take the Green Line shuttle to the Green Line, then the Blue Line, and at Metro Center exit the station and take the 60, 62 or 760 at 7th and Flower and get off at the Greyhound station.