San Diego -- Tijuana
Synopsis: This is a no-brainer. Take the 932 or the Blue Line to the border,
then walk across. At the San Ysidro station, you'll see an escher-esque ramp
across the rails from the McDonald's. Just follow the tourists and the Mexicans
into the land of the free. $2.25 if you took the bus, or $4.00 for the trolley.
Crossing the border is free, but don't be carrying anything bigger than
a shoulder bag or you might
subject yourself to a search by the Mexican border guards, and possibly import
duties. Of course, if you cross at a really busy time of day you can get away
with more stuff without much risk.