The word 買い出し implies he's going to buy a lot of stuff. My guess is that he plans to use the other guy to the full for his purpose of carrying that stuff, at least that's how the other guy took it.
I think you just need to see what follows.
From what you provided, it is
the other character means to exploit him?
The 1st and 3rd bubble is by the same character (in the panel).
The 2nd bubble says ...