I (an Intl. student) usually try to buy meals of my friends (mostly Americans i.e.) but hardly get anything in return (I really don't expect anything in return any way) i.e. they act cheaply sometimes even though they have the $$ and live affluently - this is the trend I've noticed since my undergrad years (some of my other Intl. friends have echoed similarly) Yes, I was born in a different culture, where guests mean a lot to us, but it's more than that - a sense of gesture and common-sense (may be?).