The price you get often depends on where you are. Those carts do have to pay for the right to have those locations so its not unhead of for carts in high traffic locations to be more expensive. An example: i used to work in penn plaza. My daily latte from the starbucks inside that building is $.80 more expensive than if i leave penn station and go to the starbucks on 8th ave. The mcdonalds that used to be on 42nd street used to be more expensive than the mcdonalds at 44th and 8th. Sometimes you need to walk around if you want a cheaper price.