S'right. Tacos.

They're sold by an out-of-the-way vendor in southern London for 100 Pax a pop. And they're the GREATEST ITEM IN THE GAME. What do they do? Increase your out of combat HP regeneration rate by 5-6 times for 10 seconds. Meaning one scarfed taco will put you back at full HP after a mere few seconds from being beaten to death's door by that quest boss you just killed.

The guy's name is simply "Civilian," he looks like the creature from the Black Lagoon, and he's located in a corner booth of London's Haitian Market, located approximately due south of the station.

They make the game SO much more enjoyable, for a looow low price!