This transport → hire → transport process was very redundant for Luke, but it was necessary for the Asgardians and the employees of the service factory.
Asgard was currently in a sensitive period of semi-annihilation.
They couldn't expect outsiders to help them for free, much less did they need charity.
The supplies which Luke had salvaged belonged to Asgard in the first place, and Thor would pay him back this 'service fee' in the form of a personal favor.
The Asgardians and the employees of the service factory were dealing with each other in the open, so proper business deals had to be struck.
The real gains were the high-end items which the temporary camp couldn't use. Most of them came from Odin's treasure vault, and some were from Luke's plunder in the last three months.
Luke wouldn't pocket these high-end items.