Ha, I order like Alisa!
I think the cola and burger must have very different ingredients than what we would expect. The cola could have some kind of medicine mixed in. Maybe it's something like flavored cough syrup, but marketed as a drink instead of a drug. The burger must be something like the alternative, non-meat burgers that we have today. Sort of like a tofu burger or soy burger. I don't know what exactly it would be made of, though.
Hm, maybe this is how Alis & friends earned meseta? Slay a few monsters, drag them to the local food store, and sell them to the owner, who turns them into burgers. I don't think the skeletons or zombies would make good burgers, though.