Will you buy a concert ticket at a cost of 5,000 Ariary (ca. 2 €) for someone you have only met 3 times before? Probably, if you feel like seeing the concert as well. Will you give your brand new Lowa hiking boots to one of the pousse-pousse pullers who are always lingering in front of your hotel, because he asks you to, (rightfully) claiming that his own shoes are crap for his heavily walking-reliant job? Surely not.
But what about the shades of grey between these black and white cases? How much does relative material richness oblige? Where does friendship start? And how much one-sided dependence is good for it? How much of your little finger should you give to ease your conscience, and what will you reply if the whole hand is asked a bit later?