But they are asked by Roland Stephen:
What signals are food trucks sending by pricing only in round numbers ($6, $8 etc.) unlike brick and mortar competitors (whose prices are often very similar, but expressed with lots of .95s )?
My best guess is this. You buy something from a food truck and then you eat it. You don’t keep running up a tab. (The same is true for food stalls by the way, though you may run up a tab in the hawker centre as a whole.) In a sit-down restaurant, there is a sequence of salad, main course, drinks, dessert, and so on. People might estimate their total running bill using first digits, and thus there is reason to “trick” them into thinking they have spent somewhat less than they have. The food truck doesn’t have that same incentive.
Addendum: Many of you say “to economize on change,” and maybe so. But why is this motive especially strong at food trucks? The truck clearly has the room to carry the change, and the typically urban clientele is the same group of people who are paying $6.99 plus tax somewhere else. In this context maybe speed matters more, or the percentage of cash transactions is higher to the extent many trucks do not take credit cards or wish to discourage the use of such cards.